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  2. List of prime numbers - Wikipedia

    en.wikipedia.org/wiki/List_of_prime_numbers

    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. By Euclid's theorem, there are an infinite number of prime numbers. Subsets of the prime numbers may be generated with various formulas for primes.

  3. Sieve of Eratosthenes - Wikipedia

    en.wikipedia.org/wiki/Sieve_of_Eratosthenes

    A prime number is a natural number that has exactly two distinct natural number divisors: the number 1 and itself. To find all the prime numbers less than or equal to a given integer n by Eratosthenes' method: Create a list of consecutive integers from 2 through n: (2, 3, 4, ..., n). Initially, let p equal 2, the smallest prime number.

  4. Ulam spiral - Wikipedia

    en.wikipedia.org/wiki/Ulam_spiral

    For comparison, a spiral with random odd numbers colored black (at the same density of primes in a 200x200 spiral). The Ulam spiral or prime spiral is a graphical depiction of the set of prime numbers , devised by mathematician Stanisław Ulam in 1963 and popularized in Martin Gardner 's Mathematical Games column in Scientific American a short ...

  5. List of Mersenne primes and perfect numbers - Wikipedia

    en.wikipedia.org/wiki/List_of_Mersenne_primes...

    As a result, there is a one-to-one correspondence between Mersenne primes and even perfect numbers, so a list of one can be converted into a list of the other. [1] [5] [6] It is currently an open problem whether there are infinitely many Mersenne primes and even perfect numbers.

  6. Lucky number - Wikipedia

    en.wikipedia.org/wiki/Lucky_number

    Continue removing the nth remaining numbers, where n is the next number in the list after the last surviving number. Next in this example is 9. One way that the application of the procedure differs from that of the Sieve of Eratosthenes is that for n being the number being multiplied on a specific pass, the first number eliminated on the pass is the n-th remaining number that has not yet been ...

  7. Regular prime - Wikipedia

    en.wikipedia.org/wiki/Regular_prime

    An odd prime number p is defined to be regular if it does not divide the class number of the pth cyclotomic field Q(ζ p), where ζ p is a primitive pth root of unity. The prime number 2 is often considered regular as well. The class number of the cyclotomic field is the number of ideals of the ring of integers Z(ζ p) up to equivalence.

  8. Wagstaff prime - Wikipedia

    en.wikipedia.org/wiki/Wagstaff_prime

    In number theory, a Wagstaff prime is a prime number of the form + where p is an odd prime. Wagstaff primes are named after the mathematician Samuel S. Wagstaff Jr.; the prime pages credit François Morain for naming them in a lecture at the Eurocrypt 1990 conference.

  9. Euclid number - Wikipedia

    en.wikipedia.org/wiki/Euclid_number

    Not all Euclid numbers are prime. E 6 = 13# + 1 = 30031 = 59 × 509 is the first composite Euclid number.. Every Euclid number is congruent to 3 modulo 4 since the primorial of which it is composed is twice the product of only odd primes and thus congruent to 2 modulo 4.