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 A038906 #11 Jul 08 2025 22:28:31 %S A038906 7,13,17,19,29,37,47,53,59,61,67,71,73,89,103,107,131,137,163,181,191, %T A038906 197,211,227,229,241,269,277,283,307,311,313,337,353,359,379,389,401, %U A038906 409,419,431,433,439,443,449,457 %N A038906 Primes p such that 31 is not a square mod p. %C A038906 Also, only entries p=1 (mod 4) of the sequence are not squares mod 31 (from the quadratic reciprocity law). - _Lekraj Beedassy_, Jul 21 2004 %H A038906 Vincenzo Librandi, <a href="/A038906/b038906.txt">Table of n, a(n) for n = 1..1000</a> %t A038906 Select[Prime@Range[120], JacobiSymbol[31, #] == -1 &] (* _Vincenzo Librandi_, Sep 09 2012 *) %K A038906 nonn %O A038906 1,1 %A A038906 _N. J. A. Sloane_ %E A038906 Offset changed from 0 to 1 by _Vincenzo Librandi_, Sep 09 2012