The question is still awfully phrased. about it-- if we don't think about the Other examples of Fibonacci primes are 233 and 1597. For example, his law predicts 72 primes between 1,000,000 and 1,001,000. For example, it is used in the proof that the square root of 2 is irrational. The most notable problem is The Fundamental Theorem of Arithmetic, which says any number greater than 1 has a unique prime factorization. The goal is to compute \(2^{90}\bmod{91}.\). So maybe there is no Google-accessible list of all $13$ digit primes on . Feb 22, 2011 at 5:31. In an examination of twenty questions, each correct answer carries 5 marks, each unanswered question carries 1 mark and each wrong answer carries 0 marks. Officer, MP Vyapam Horticulture Development Officer, Patna Civil Court Reader Cum Deposition Writer, NDA (Held On: 18 Apr 2021) Maths Previous Year paper, Electric charges and coulomb's law (Basic), Copyright 2014-2022 Testbook Edu Solutions Pvt. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Discoverers denoted as "GIMPS / name" refer to GIMPS discoveries with hardware used by that person. our constraint. Books C and D are to be arranged first and second starting from the right of the shelf. be a little confusing, but when we see How many five-digit flippy numbers are divisible by . Learn more about Stack Overflow the company, and our products. This means that each positive integer has a prime factorization that no other positive integer has, and the order of factors in a prime factorization does not matter. Direct link to SLow's post Why is one not a prime nu, Posted 2 years ago. After 2, 3, and 5, every prime leaves remainder 1, 7, 11, 13, 17, 19, 23, or 29 modulo 30. For more see Prime Number Lists. Prime Numbers in the range 100,000 to 200,000, Prime Numbers in the range 200,000 to 300,000, Prime Numbers in the range 300,000 to 400,000, Prime Numbers in the range 400,000 to 500,000, Prime Numbers in the range 500,000 to 600,000, Prime Numbers in the range 600,000 to 700,000, Prime Numbers in the range 700,000 to 800,000, Prime Numbers in the range 800,000 to 900,000, Prime Numbers in the range 900,000 to 1,000,000. 73. plausible given nation-state resources. natural numbers-- 1, 2, and 4. So one of the digits in each number has to be 5. Direct link to Victor's post Why does a prime number h, Posted 10 years ago. So it's divisible by three For example, 2, 3, 5, 13 and 89. A train 100 metres long, moving at a speed of 50 km per hour, crosses another train 120 metres long coming from the opposite direction in 6 seconds. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. There are $308,457,624,821$ 13 digit primes and $26,639,628,671,867$ 15 digit primes. Let's move on to 7. By contrast, numbers with more than 2 factors are call composite numbers. Use the method of repeated squares. I find it very surprising that there are only a finite number of truncatable primes (and even more surprising that there are only 11)! haven't broken it down much. So 7 is prime. By using our site, you Very good answer. Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It means that something is opposite of common-sense expectations but still true.Hope that helps! But as you progress through From 21 through 30, there are only 2 primes: 23 and 29. This specifically means that there is a prime between $10^n$ and $10\cdot 10^n$. Although one can keep going, there is seldom any benefit. And I'll circle From the list above, it might seem as though Mersenne primes are relatively easy to find by simply plugging in prime numbers into \(2^p-1\). How many semiprimes, etc? If you're seeing this message, it means we're having trouble loading external resources on our website. When it came to math.stackexchage it was a set of questions of simple mathematical fact, which could be answered without regard to the motivation. How many primes under 10^10? Common questions. Then \(\frac{M_p\big(M_p+1\big)}{2}\) is an even perfect number. That is, an emirpimes is a semiprime that is also a (distinct) semiprime upon reversing its digits. mixture of sand and iron, 20% is iron. Identify those arcade games from a 1983 Brazilian music video. The bounds from Wikipedia $\frac{x}{\log x + 2} < \pi(x) < \frac{x}{\log x - 4}$ for $x> 55$ can be used to show that there is always a prime with $n$ digits for $n\ge 3$. Let's try out 3. \text{lcm}(36,48) &= 2^{\max(2,4)} \times 3^{\max(2,1)} \\ The numbers p corresponding to Mersenne primes must themselves . Share Cite Follow \(53\) doesn't have any other divisor other than one and itself, so it is indeed a prime: \(m=53.\). One of the flags actually asked for deletion. That means that your prime numbers are on the order of 2^512: over 150 digits long. For instance, in the case of p = 2, 22 1 = 3 is prime, and 22 1 (22 1) = 2 3 = 6 is perfect. that it is divisible by. Prime numbers from 1 to 10 are 2,3,5 and 7. A prime number is a numberthat can be divided exactly only by itself(example - 2, 3, 5, 7, 11 etc.). 2^{2^3} &\equiv 74 \pmod{91} \\ special case of 1, prime numbers are kind of these So it does not meet our 68,000, it is a golden opportunity for all job seekers. This question appears to be off-topic because it is not about programming. [2][6] The frequency of Mersenne primes is the subject of the LenstraPomeranceWagstaff conjecture, which states that the expected number of Mersenne primes less than some given x is (e / log 2) log log x, where e is Euler's number, is Euler's constant, and log is the natural logarithm. \(49\) is divisible by \(7\), and from the property of primes it is enough information to conclude that the number is not prime. But what can mods do here? 4 = last 2 digits should be multiple of 4. But, it was closed & deleted at OP's request. Before I show you the list, here's how to generate a list of prime numbers of your own using a few popular languages. I tried (and still trying) to be loyal to the key mathematical problems which people smocked in Security.SO to be just math homework. 840. 3 doesn't go. This conjecture states that every even integer greater than 2 can be expressed as the sum of two primes. We know exists modulo because 2 is relatively prime to 3, so we conclude that (i.e. . Thumbs up :). 48 &= 2^4 \times 3^1. For example, the prime gap between 13 and 17 is 4. I'm not entirely sure what the OP is trying to ask, or exactly what the mild scuffle in the comments is about (and consequently I'm not sure what the appropriate moderator reaction is). List out numbers, eliminate the numbers that have a prime divisor that is not the number itself, and the remaining numbers will be prime. 8, you could have 4 times 4. This is the complete index for the prime curiosity collection--an exciting collection of curiosities, wonders and trivia related to prime numbers and integer factorization. This is due to the Lucas-Lehmer primality test, which is an efficient algorithm that is specific to testing primes of the form \(2^p-1\). Why can't it also be divisible by decimals? Hereof, Is 1 a prime number? But remember, part A prime number will have only two factors, 1 and the number itself; 2 is the only even . What is the best way to figure out if a number (especially a large number) is prime? Direct link to digimax604's post At 2:08 what does counter, Posted 5 years ago. A prime number is a natural number greater than 1 that has no positive integer divisors other than 1 and itself. And if you're irrational numbers and decimals and all the rest, just regular try a really hard one that tends to trip people up. examples here, and let's figure out if some \(_\square\). But the, "which means the prime numbers range from 512 to 2048" - I think you mean 512 to 2048. &\vdots\\ Prime factorization can help with the computation of GCD and LCM. Any 3 digit palindrome number is of type "aba" where b can be chosen from the numbers 0 to 9 and a can be chosen from 1 to 9. Direct link to cheryl.hoppe's post Is pi prime or composite?, Posted 10 years ago. 1 and 17 will It is divisible by 2. In the following sequence, how many prime numbers are present? To crack (or create) a private key, one has to combine the right pair of prime numbers. A train leaves Meerutat 5 a.m. and reaches Delhi at 9 a.m. Another train leaves Delhi at 7 a.m. and reaches Meerutat 10:30 a.m. At what time do the two trains cross each other? Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. say it that way. What is know about the gaps between primes? The nature of simulating nature: A Q&A with IBM Quantum researcher Dr. Jamie We've added a "Necessary cookies only" option to the cookie consent popup. For instance, I might say that 24 = 3 x 2 x 2 x 2 and you might say 24 = 2 x 2 x 3 x 2, but we each came up with three 2's and one 3 and nobody else could do differently. 6= 2* 3, (2 and 3 being prime). \end{align}\], So, no numbers in the given sequence are prime numbers. a little counter intuitive is not prime. video here and try to figure out for yourself The next couple of examples demonstrate this. The next prime number is 10,007. 15,600 to Rs. We'll think about that Does ZnSO4 + H2 at high pressure reverses to Zn + H2SO4? The simplest way to identify prime numbers is to use the process of elimination. As for whether collisions are possible- modern key sizes (depending on your desired security) range from 1024 to 4096, which means the prime numbers range from 512 to 2048 bits. straightforward concept. divisible by 1 and 16. The Fundamental Theorem of Arithmetic states that every number is either prime or is the product of a list of prime numbers, and that list is unique aside from the order the terms appear in. The difference between the phonemes /p/ and /b/ in Japanese. The five digit number A679B, in base ten, is divisible by 72. 3 times 17 is 51. A perfect number is a positive integer that is equal to the sum of its proper positive divisors. Find the cost of fencing it at the rate of Rs. So instead of solving the key mathematical problem they wasted time on trivialities, the hidden mathematical problem stayed unsolved. pretty straightforward. Is there a solution to add special characters from software and how to do it. If you can find anything natural ones are whole and not fractions and negatives. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? Euclid's lemma can seem innocuous, but it is incredibly important for many proofs in number theory. It was unfortunate that the question went through many sites, becoming more confused, but it is in a way understandable because it is related to all of them. How many natural We can arrange the number as we want so last digit rule we can check later. The number of different committees that can be formed from 5 teachers and 10 students is, If each element of a determinant of third order with value A is multiplied by 3, then the value of newly formed determinant is, If the coefficients of x7 and x8 in \(\left(2+\frac{x}{3}\right)^n\) are equal, then n is, The number of terms in the expansion of (x + y + z)10 is, If 2, 3 be the roots of 2x3+ mx2- 13x + n = 0 then the values of m and n are respectively, A person is to count 4500 currency notes. This definition excludes the related palindromic primes. break. How to use Slater Type Orbitals as a basis functions in matrix method correctly? be a priority for the Internet community. Although Mersenne primes continue to be discovered, it is an open problem whether or not there are an infinite number of them. One of those numbers is itself, If you have only two 123454321&= 1111111111. It's not divisible by 2. List of Mersenne primes and perfect numbers, The first four perfect numbers were documented by, It has not been verified whether any undiscovered Mersenne primes exist between the 48th (, "Mersenne Primes: History, Theorems and Lists", "Perfect Numbers, Abundant Numbers, and Deficient Numbers", "Characterizing all even perfect numbers", "Heuristics Model for the Distribution of Mersennes", "Recent developments in primality testing", "The Largest Known prime by Year: A Brief History", "Euclid's Elements, Book IX, Proposition 36", "Modular restrictions on Mersenne divisors", "Extrait d'un lettre de M. Euler le pere M. Bernoulli concernant le Mmoire imprim parmi ceux de 1771, p 318", "Sur un nouveau nombre premier, annonc par le pre Pervouchine", "Note sur l'application des sries rcurrentes la recherche de la loi de distribution des nombres premiers", Comptes rendus de l'Acadmie des Sciences, "Three new Mersenne primes and a statistical theory", "Supercomputer Comes Up With Whopping Prime Number", "Largest Known Prime Number Discovered on Cray Research Supercomputer", "Crunching numbers: Researchers come up with prime math discovery", "GIMPS Discovers 45th and 46th Mersenne Primes, 2, "University professor discovers largest prime number to date", "GIMPS Project Discovers Largest Known Prime Number: 2, "Largest known prime number discovered in Missouri", "Why You Should Care About a Prime Number That's 23,249,425 Digits Long", "GIMPS Discovers Largest Known Prime Number: 2, "The World Has A New Largest-Known Prime Number", sequence A000043 (Corresponding exponents, List on GIMPS, with the full values of large numbers, A technical report on the history of Mersenne numbers, by Guy Haworth, https://en.wikipedia.org/w/index.php?title=List_of_Mersenne_primes_and_perfect_numbers&oldid=1142343814, LLT / Prime95 on PC with 2.4 GHz Pentium 4 processor, LLT / Prime95 on PC at University of Central Missouri, LLT / Prime95 on PC with Intel Core i5-6600 processor, LLT / Prime95 on PC with Intel Core i5-4590T processor, This page was last edited on 1 March 2023, at 22:03. Each Mersenne prime corresponds to an even perfect number: Let \(M_p\) be a Mersenne prime. 6!&=720\\ Candidates who are qualified for the CBT round of the DFCCIL Junior Executive are eligible for the Document Verification & Medical Examination. Therefore, \(p\) divides their sum, which is \(b\). The first few prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23 and 29. (4) The letters of the alphabet are given numeric values based on the two conditions below. one, then you are prime. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. The Riemann hypothesis relates the real parts of the zeros of the Riemann zeta function to the oscillations of the prime numbers about their "expected" positions given the estimation of the prime counting function above. In fact, many of the largest known prime numbers are Mersenne primes. \(2^{11}-1=2047\) is not a prime number; its prime factorization is \(23 \times 89.\). The answer is that the largest known prime has over 17 million digits- far beyond even the very large numbers typically used in cryptography). View the Prime Numbers in the range 0 to 10,000 in a neatly formatted table, or download any of the following text files: I generated these prime numbers using the "Sieve of Eratosthenes" algorithm. :), Creative Commons Attribution/Non-Commercial/Share-Alike. say, hey, 6 is 2 times 3. I favor deletion due to "fundamentally flawed and poorly (re)written question" unless anyone objects. When the "a" part, or real part, of "s" is equal to 1/2, there arises a common problem in number theory, called the Riemann Hypothesis, which says that all of the non-trivial zeroes of the function lie on that real line 1/2. \(51\) is divisible by \(3\). \(101\) has no factors other than 1 and itself. p & 2^p-1= & M_p\\ Another way to Identify prime numbers is as follows: What is the next term in the following sequence? So, any combination of the number gives us sum of15 that will not be a prime number. Direct link to noe's post why is 1 not prime?, Posted 11 years ago. When using prime numbers and composite numbers, stick to whole numbers, because if you are factoring out a number like 9, you wouldn't say its prime factorization is 2 x 4.5, you'd say it was 3 x 3, because there is an endless number of decimals you could use to get a whole number. When both the numerator and denominator are decreased by 6, then the denominator becomes 12 times the numerator. This process can be visualized with the sieve of Eratosthenes. Numbers that have more than two factors are called composite numbers. 94 is divided into two parts in such a way that the fifth part of the first and the eighth part of the second are in the ratio 3 : 4 The first part is: The denominator of a fraction is 4 more than twice the numerator. \(_\square\). The number of different orders in which books A, B and E may be arranged is, A school committee consists of 2 teachers and 4 students. 997 is not divisible by any prime number up to \(31,\) so it must be prime. The highest power of 2 that 48 is divisible by is \(16=2^4.\) The highest power of 3 that 48 is divisible by is \(3=3^1.\) Thus, the prime factorization of 48 is, The fundamental theorem of arithmetic guarantees that no other positive integer has this prime factorization. \end{align}\]. How many two digit numbers are there such that the product of their digits after reducing it to the smallest form is a prime number? 2^{2^4} &\equiv 16 \pmod{91} \\ However, this theorem does give insight that a number's primality is not linked purely to the divisors of that number. So clearly, any number is If you don't know Multiplying both sides of this equation by \(b\) gives \(b=uab+vpb\). you a hard one. Each number has the same primes, 2 and 3, in its prime factorization. \end{align}\]. The simple interest on a certain sum of money at the rate of 5 p.a. That means that among these 10^150 numbers, there are approximately 10^150/ln(10^150) primes, which works out to 2.8x10^147 primes to choose from- certainly more than you could fit into any list!! divisible by 1 and itself. It is therefore sufficient to test 2, 3, 5, 7, 11, and 13 for divisibility. the second and fourth digit of the number) . Let \(p\) be prime. Fortunately, one does not need to test the divisibility of each smaller prime to conclude that a number is prime. There are only finitely many, indeed there are none with more than 3 digits. Since there are only four possible prime numbers in the range [0, 9] and every digit for sure lies in this range, we only need to check the number of digits equal to either of the elements in the set {2, 3, 5, 7}. Not a single five-digit prime number can be formed using the digits 1, 2, 3, 4, 5 (without repetition). When we look at \(47,\) it doesn't have any divisor other than one and itself. flags). Is it impossible to publish a list of all the prime numbers in the range used by RSA? How to follow the signal when reading the schematic? It only takes a minute to sign up. How to tell which packages are held back due to phased updates. What is the greatest number of beads that can be arranged in a row? It is helpful to have a list of prime numbers handy in order to know which prime numbers should be tested. numbers that are prime. What is the harm in considering 1 a prime number? Redoing the align environment with a specific formatting. A palindromic number (also known as a numeral palindrome or a numeric palindrome) is a number (such as 16461) that remains the same when its digits are reversed.In other words, it has reflectional symmetry across a vertical axis. It's divisible by exactly This process might seem tedious to do by hand, but a computer could perform these calculations relatively efficiently. If you think about it, 7 is equal to 1 times 7, and in that case, you really For any integer \(n>3,\) there always exists at least one prime number \(p\) such that, This implies that for the \(k^\text{th}\) prime number, \(p_k,\) the next consecutive prime number is subject to. \[2, 3, 5, 7, 11, 13, 17, 19, 23, 29, \ldots \]. Using this definition, 1 By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Compute 90 in binary: Compute the residues of the repeated squares of 2: \[\begin{align} Which one of the following marks is not possible? Ltd.: All rights reserved. So 2 is prime. He talks about techniques for interchanging sequences in a summation like I did at the start very early on, introduces the vonmangoldt function on the chapter about arithmetic functions, introduces Euler products later on too, he further . Prime and Composite Numbers Prime Numbers - Advanced Prime Number Lists. 2 & 2^2-1= & 3 \\ Replacing broken pins/legs on a DIP IC package. else that goes into this, then you know you're not prime. Furthermore, every integer greater than 1 has a unique prime factorization up to the order of the factors. To take a concrete example, for N = 10 22, 1 / ln ( N) is about 0.02, so one would expect only about 2 % of 22 -digit numbers to be prime. 2^{2^2} &\equiv 16 \pmod{91} \\ The research also shows a flaw in TLS that could allow a man-in-middle attacker to downgrade the encryption to 512 bit. m-hikari.com/ijcms-password/ijcms-password13-16-2006/, We've added a "Necessary cookies only" option to the cookie consent popup, Extending prime numbers digit by digit while retaining primality. So let's start with the smallest Explanation: Digits of the number - {1, 2} But, only 2 is prime number. {10^1000, 10^1001}]" generates a random 1000 digit prime in 0.40625 seconds on my five year old desktop machine. And there are enough prime numbers that there have never been any collisions? 2^{2^6} &\equiv 16 \pmod{91} \\ So, 15 is not a prime number. And the definition might These kinds of tests are designed to either confirm that the number is composite, or to use probability to designate a number as a probable prime. rev2023.3.3.43278. A committee of 3 persons is to be formed by choosing from three men and 3 women in which at least one is a woman. For example, 5 is a prime number because it has no positive divisors other than 1 and 5. Is it possible to rotate a window 90 degrees if it has the same length and width? Why does Mister Mxyzptlk need to have a weakness in the comics? yes. 1 is divisible by only one Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. And maybe some of the encryption How many two-digit primes are there between 10 and 99 which are also prime when reversed? [11] The discovery year and discoverer are of the Mersenne prime, since the perfect number immediately follows by the EuclidEuler theorem. the prime numbers. 31. Direct link to Sonata's post All numbers are divisible, Posted 12 years ago. none of those numbers, nothing between 1 Thanks! break them down into products of So hopefully that Weekly Problem 18 - 2016 . This reduces the number of modular reductions by 4/5. at 1, or you could say the positive integers. Testing primes with this theorem is very inefficient, perhaps even more so than testing prime divisors. This is a list of articles about prime numbers.A prime number (or prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself. \end{align}\]. Only the numeric values of 2,1,0,1 and 2 are used. So if you can find anything Five different books (A, B, C, D and E) are to be arranged on a shelf. This number is also the largest known prime number. An example of a probabilistic prime test is the Fermat primality test, which is based on Fermat's little theorem. The area of a circular field is 13.86 hectares. How many circular primes are there below one million? Now \(p\) divides \(uab\) \((\)since it is given that \(p \mid ab),\) and \(p\) also divides \(vpb\). How to notate a grace note at the start of a bar with lilypond? And the way I think as a product of prime numbers. m&=p_1^{j_1} \times p_2^{j_2} \times p_3^{j_3} \times \cdots\\ of them, if you're only divisible by yourself and \end{align}\]. But it's also divisible by 7. Is 51 prime? I'll switch to Otherwise, \(n\), Repeat these steps any number of times. Prime numbers act as "building blocks" of numbers, and as such, it is important to understand prime numbers to understand how numbers are related to each other. It is divisible by 1. For example, the first 5 prime numbers are 2, 3, 5, 7, and 11. numbers are pretty important. This is very far from the truth. of factors here above and beyond divisible by 1 and 3. All non-palindromic permutable primes are emirps. So it won't be prime. This, along with integer factorization, has no algorithm in polynomial time. Or is that list sufficiently large to make this brute force attack unlikely? So it has four natural 119 is divisible by 7, so it is not a prime number. 3 & 2^3-1= & 7 \\ 4 men board a bus which has 6 vacant seats. Practice math and science questions on the Brilliant iOS app. Jeff's open design works perfect: people can freely see my view and Cris's view. 1 is the only positive integer that is neither prime nor composite. It has been known for a long time that there are infinitely many primes. Prime numbers are critical for the study of number theory. Adjacent Factors Thus the probability that a prime is selected at random is 15/50 = 30%. I left there notices and down-voted but it distracted more the discussion. The odds being able to do so quickly turn against you. I hope mod won't waste too much time on this. So it's got a ton The fundamental theorem of arithmetic separates positive integers into two classifications: prime or composite. In theory-- and in prime This reduction of cases can be extended. From 1 through 10, there are 4 primes: 2, 3, 5, and 7. One of the most fundamental theorems about prime numbers is Euclid's lemma. +1 I like Ross's way of doing things, just forget the junk and concentrate on important things: mathematics in the question. 2^{90} &\equiv (16)(16)(74)(4) \pmod{91} \\ [10], The following is a list of all currently known Mersenne primes and perfect numbers, along with their corresponding exponents p. As of 2022[update], there are 51 known Mersenne primes (and therefore perfect numbers), the largest 17 of which have been discovered by the distributed computing project Great Internet Mersenne Prime Search, or GIMPS. Suppose \(p\) does not divide \(a\). 211 is not divisible by any of those numbers, so it must be prime. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. because one of the numbers is itself. building blocks of numbers. [3] Meanwhile, perfect numbers are natural numbers that equal the sum of their positive proper divisors, which are divisors excluding the number itself. Given a positive integer \(n\), Euler's totient function, denoted by \(\phi(n),\) gives the number of positive integers less than \(n\) that are co-prime to \(n.\), Listing out the positive integers that are less than 10 gives. You can read them now in the comments between Fixee and me. implying it is the second largest two-digit prime number. the idea of a prime number. 3, so essentially the counting numbers starting With the side note that Bertrand's postulate is a (proved) theorem. idea of cryptography. 12321&= 111111\\ Making statements based on opinion; back them up with references or personal experience. How to match a specific column position till the end of line? two natural numbers. precomputation for a single 1024-bit group would allow passive . Each repetition of these steps improves the probability that the number is prime. I'll circle the The Dedicated Freight Corridor Corporation of India Limited (DFCCIL) has released the DFCCIL Junior Executive Result for Mechanical and Signal & Telecommunication against Advt No. kind of a strange number. Previous . The prime numbers of this size can fit in RAM incredibly easily- they range from 1-4 kb. divisible by 1 and 4. Asking for help, clarification, or responding to other answers. \hline Thanks for contributing an answer to Stack Overflow! \(2^{6}-1=63\), which is divisible by 7, so it isn't prime. Mersenne primes, named after the friar Marin Mersenne, are prime numbers that can be expressed as 2p 1 for some positive integer p. For example, 3 is a Mersenne prime as it is a prime number and is expressible as 22 1. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Why not just ask for the number of 10 digit numbers with at most 1,2,3 prime factors, clarifying straight away, whether or not you are interested in repeated factors and whether trailing zeros are allowed? But if we let 1 be prime we could write it as 6=1*2*3 or 6= 1*2 *1 *3. The problem is that it assumes a perfect PRNG to generate this amount of unique numbers to derive the primes from. I think you get the Main Article: Fundamental Theorem of Arithmetic. Let andenote the number of notes he counts in the nthminute. Long division should be used to test larger prime numbers for divisibility. In how many different ways can they stay in each of the different hotels? However, the question of how prime numbers are distributed across the integers is only partially understood.