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  2. Twin prime - Wikipedia

    en.wikipedia.org/wiki/Twin_prime

    An isolated prime (also known as single prime or non-twin prime) is a prime number p such that neither p − 2 nor p + 2 is prime. In other words, p is not part of a twin prime pair. For example, 23 is an isolated prime, since 21 and 25 are both composite. The first few isolated primes are 2, 23, 37, 47, 53, 67, 79, 83, 89, 97, ...

  3. Brun's theorem - Wikipedia

    en.wikipedia.org/wiki/Brun's_theorem

    The convergence to Brun's constant. In number theory, Brun's theorem states that the sum of the reciprocals of the twin primes (pairs of prime numbers which differ by 2) converges to a finite value known as Brun's constant, usually denoted by B 2 (sequence A065421 in the OEIS).

  4. Chen prime - Wikipedia

    en.wikipedia.org/wiki/Chen_prime

    In mathematics, a prime number p is called a Chen prime if p + 2 is either a prime or a product of two primes (also called a semiprime). The even number 2 p + 2 therefore satisfies Chen's theorem . The Chen primes are named after Chen Jingrun , who proved in 1966 that there are infinitely many such primes.

  5. Table of congruences - Wikipedia

    en.wikipedia.org/wiki/Table_of_congruences

    Clement's congruence-based theorem characterizes the twin primes pairs of the form (, +) through the following conditions: [()! +] ((+)), +P. A. Clement's original 1949 paper [2] provides a proof of this interesting elementary number theoretic criteria for twin primality based on Wilson's theorem.

  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. Formula for primes - Wikipedia

    en.wikipedia.org/wiki/Formula_for_primes

    Because the set of primes is a computably enumerable set, by Matiyasevich's theorem, it can be obtained from a system of Diophantine equations. Jones et al. (1976) found an explicit set of 14 Diophantine equations in 26 variables, such that a given number k + 2 is prime if and only if that system has a solution in nonnegative integers: [7]

  8. List of prime numbers - Wikipedia

    en.wikipedia.org/wiki/List_of_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 .

  9. Chen's theorem - Wikipedia

    en.wikipedia.org/wiki/Chen's_theorem

    Chen's 1973 paper stated two results with nearly identical proofs. [2]: 158 His Theorem I, on the Goldbach conjecture, was stated above.His Theorem II is a result on the twin prime conjecture.