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 A216740 #5 Sep 15 2012 12:39:57 %S A216740 5,7,13,19,23,29,31,37,47,53,61,67,71,73,79,97,101,103,109,127,139, %T A216740 149,151,157,163,167,173,181,191,193,197,199,211,223,229,239,241,263, %U A216740 269,271,277,293,307,311,313,317,331,337,349,359,367,373,379 %N A216740 Primes p such that x^18 = -2 has no solution mod p. %C A216740 Complement of A051078 relative to A000040. %H A216740 Vincenzo Librandi, <a href="/A216740/b216740.txt">Table of n, a(n) for n = 1..1000</a> %t A216740 ok[p_]:= Reduce[Mod[x^18 + 2, p] == 0, x, Integers] == False; Select[Prime[Range[100]], ok] %Y A216740 Cf. A000040, A051078. %K A216740 nonn,easy %O A216740 1,1 %A A216740 _Vincenzo Librandi_, Sep 15 2012