Second sequence ever computed by electronic computer, on EDSAC, (see Renwick link). a( A000720(n)) = n if (and only if) n is prime.

$list of prime numbers 1 to 10000$

Prime(n) and pi(n) are inverse functions: A000720(a(n)) = n and a(n) is the least number m such that a( A000720(m)) = a(n). This shows that there exist infinitely many prime numbers.' - Pieter Moree, Oct 14 2004ДЎ is not a prime, for if the primes included 1, then the factorization of a natural number n into a product of primes would not be unique, since n = n*1. The paper by Kaoru Motose starts as follows: 'Let q be a prime divisor of a Mersenne number 2^p-1 where p is prime.

For contributions concerning 'almost primes' see A002808.ДЄ number p is prime if (and only if) it is greater than 1 and has no positive divisors except 1 and p.ДЄ natural number is prime if and only if it has exactly two (positive) divisors.ДЄ prime has exactly one proper positive divisor, 1. For all information concerning prime powers, see A000961. A000040 - OEIS login The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

List of prime numbers 1 to 10000