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 A040116 #10 Jul 08 2025 22:48:33
%S A040116 2,3,7,11,13,19,23,31,37,43,47,59,61,67,71,73,79,83,97,103,107,109,
%T A040116 127,131,139,151,157,163,167,179,181,191,193,199,211,223,227,229,239,
%U A040116 241,251,263,271,277,283,307,311
%N A040116 Primes p such that x^4 = 9 has a solution mod p.
%H A040116 Vincenzo Librandi, <a href="/A040116/b040116.txt">Table of n, a(n) for n = 1..1000</a>
%t A040116 ok [p_]:=Reduce[Mod[x^4 - 9, p]== 0, x, Integers]=!= False; Select[Prime[Range[170]], ok] (* _Vincenzo Librandi_, Sep 12 2012 *)
%o A040116 (Magma) [p: p in PrimesUpTo(400) | exists(t){x : x in ResidueClassRing(p) | x^4 eq 9}]; // _Vincenzo Librandi_, Sep 12 2012
%K A040116 nonn,easy
%O A040116 1,1
%A A040116 _N. J. A. Sloane_