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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

    The Miller–Rabin primality test or Rabin–Miller primality test is a probabilistic primality test: an algorithm which determines whether a given number is likely to be prime, similar to the Fermat primality test and the Solovay–Strassen primality test. It is of historical significance in the search for a polynomial-time deterministic ...

  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. 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 ...

  7. Lucas–Lehmer primality test - Wikipedia

    en.wikipedia.org/wiki/Lucas–Lehmer_primality_test

    The Mersenne number M 3 = 2 3 −1 = 7 is prime. The Lucas–Lehmer test verifies this as follows. Initially s is set to 4 and then is updated 3−2 = 1 time: s ← ( (4 × 4) − 2) mod 7 = 0. Since the final value of s is 0, the conclusion is that M 3 is prime. On the other hand, M 11 = 2047 = 23 × 89 is not prime.

  8. Prime number theorem - Wikipedia

    en.wikipedia.org/wiki/Prime_number_theorem

    All instances of log (x) without a subscript base should be interpreted as a natural logarithm, also commonly written as ln (x) or loge(x). In mathematics, the prime number theorem (PNT) describes the asymptotic distribution of the prime numbers among the positive integers. It formalizes the intuitive idea that primes become less common as they ...

  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.