This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A156655 #14 Sep 02 2018 12:34:35 %S A156655 3001,4001,7001,9001,13001,16001,19001,21001,24001,28001,51001,54001, %T A156655 55001,61001,69001,70001,76001,81001,88001,90001,93001,96001,97001, %U A156655 102001,103001,109001,114001,115001,121001,123001,124001,126001,129001 %N A156655 Primes of the form 1000*k + 1. %C A156655 Let d be any divisors of 1000, then d and -d are quadratic residues modulo these primes. All terms are of the form x^2 - d*y^2 for d = -40, -25, -10, -8, -5, -4, -2, -1, 2, 5, 8, 10. Conjecture: they are also of the form x^2 - d*y^2 for d = 20, 40, 50, 200. - _Jianing Song_, Aug 29 2018 %o A156655 (PARI) for(k=0, 130, if(isprime(1000*k+1), print1(1000*k+1, ", "))) \\ _Jianing Song_, Aug 29 2018 %Y A156655 Cf. A064962. %K A156655 nonn %O A156655 1,1 %A A156655 Avik Roy (avik_3.1416(AT)yahoo.co.in), Feb 12 2009 %E A156655 More terms from _R. J. Mathar_, Feb 19 2009