Prime divisors of Mersenne numbers. Primes p such that the multiplicative order of 2 modulo p is prime.
3, 7, 23, 31, 47, 89, 127, 167, 223, 233, 263, 359, 383, 431, 439, 479, 503, 719, 839
1 seqfan posts
Sun Sep 19 20:16:04 CEST 2010 [seqfan] Re: Nonmembers of Range of Euler Phi Function