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  2. Formula for primes - Wikipedia

    en.wikipedia.org/wiki/Formula_for_primes

    However, it does not contain all the prime numbers, since the terms gcd(n + 1, a n) are always odd and so never equal to 2. 587 is the smallest prime (other than 2) not appearing in the first 10,000 outcomes that are different from 1. Nevertheless, in the same paper it was conjectured to contain all odd primes, even though it is rather inefficient.

  3. 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.

  4. Primality test - Wikipedia

    en.wikipedia.org/wiki/Primality_test

    A primality test is an algorithm for determining whether an input number is prime.Among other fields of mathematics, it is used for cryptography.Unlike integer factorization, primality tests do not generally give prime factors, only stating whether the input number is prime or not.

  5. Euclid's lemma - Wikipedia

    en.wikipedia.org/wiki/Euclid's_lemma

    Any prime number is prime to any number it does not measure. [note 6] Proposition 30 If two numbers, by multiplying one another, make the same number, and any prime number measures the product, it also measures one of the original numbers. [note 7] Proof of 30 If c, a prime number, measure ab, c measures either a or b. Suppose c does not measure a.

  6. Wilson's theorem - Wikipedia

    en.wikipedia.org/wiki/Wilson's_theorem

    We can use this fact to prove part of a famous result: for any prime p such that p ≡ 1 (mod 4), the number (−1) is a square (quadratic residue) mod p. For this, suppose p = 4 k + 1 for some integer k .

  7. Lucas primality test - Wikipedia

    en.wikipedia.org/wiki/Lucas_primality_test

    In computational number theory, the Lucas test is a primality test for a natural number n; it requires that the prime factors of n − 1 be already known. [ 1 ] [ 2 ] It is the basis of the Pratt certificate that gives a concise verification that n is prime.

  8. Fermat primality test - Wikipedia

    en.wikipedia.org/wiki/Fermat_primality_test

    Using fast algorithms for modular exponentiation and multiprecision multiplication, the running time of this algorithm is O(k log 2 n log log n) = Õ(k log 2 n), where k is the number of times we test a random a, and n is the value we want to test for primality; see Miller–Rabin primality test for details.

  9. Primitive recursive function - Wikipedia

    en.wikipedia.org/wiki/Primitive_recursive_function

    Pr(a): a is a prime number Pr(a) = def a>1 & NOT(Exists c) 1<c<a [ c|a ] p i: the i+1th prime number (a) i: exponent of p i in a: the unique x such that p i x |a & NOT(p i x' |a) lh(a): the "length" or number of non-vanishing exponents in a; lo(a, b): (logarithm of a to base b): If a, b > 1 then the greatest x such that b x | a else 0