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  2. Primality test - Wikipedia

    en.wikipedia.org/wiki/Primality_test

    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.

  3. Formula for primes - Wikipedia

    en.wikipedia.org/wiki/Formula_for_primes

    Formula for primes. In number theory, a formula for primes is a formula generating the prime numbers, exactly and without exception. Formulas for calculating primes do exist; however, they are computationally very slow. A number of constraints are known, showing what such a "formula" can and cannot be.

  4. Miller–Rabin primality test - Wikipedia

    en.wikipedia.org/wiki/Miller–Rabin_primality_test

    Input #1: b, the number of bits of the result Input #2: k, the number of rounds of testing to perform Output: a strong probable prime n while True: pick a random odd integer n in the range [2 b−1, 2 b −1] if the Miller–Rabin test with inputs n and k returns “probably prime” then return n

  5. Fermat primality test - Wikipedia

    en.wikipedia.org/wiki/Fermat_primality_test

    Concept. Fermat's little theorem states that if p is prime and a is not divisible by p, then. If one wants to test whether p is prime, then we can pick random integers a not divisible by p and see whether the congruence holds. If it does not hold for a value of a, then p is composite. This congruence is unlikely to hold for a random a if p is ...

  6. Pollard's p − 1 algorithm - Wikipedia

    en.wikipedia.org/wiki/Pollard%27s_p_%E2%88%92_1...

    Assume that p − 1, where p is the smallest prime factor of n, can be modelled as a random number of size less than √ n. By Dixon's theorem , the probability that the largest factor of such a number is less than ( p − 1) 1/ε is roughly ε − ε ; so there is a probability of about 3 −3 = 1/27 that a B value of n 1/6 will yield a ...

  7. Prime number - Wikipedia

    en.wikipedia.org/wiki/Prime_number

    A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways of writing it as a product, 1 × 5 or 5 × 1, involve 5 itself. However, 4 is composite because it is a ...

  8. Sieve of Atkin - Wikipedia

    en.wikipedia.org/wiki/Sieve_of_Atkin

    The following is pseudocode which combines Atkin's algorithms 3.1, 3.2, and 3.3 [1] by using a combined set "s" of all the numbers modulo 60 excluding those which are multiples of the prime numbers 2, 3, and 5, as per the algorithms, for a straightforward version of the algorithm that supports optional bit packing of the wheel; although not specifically mentioned in the referenced paper, this ...

  9. Lucas primality test - Wikipedia

    en.wikipedia.org/wiki/Lucas_primality_test

    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.