Primes p such that 2 is a square mod p; or, primes congruent to {1, 2, 7} mod 8.
2, 7, 17, 23, 31, 41, 47, 71, 73, 79, 89, 97, 103, 113, 127, 137, 151, 167, 191, 193
1 seqfan posts
Sat Oct 10 20:36:40 CEST 2009 [seqfan] Re: A006451 = n such that n*(n+1)/2+1 is square?