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 A216752 #7 Sep 08 2022 08:46:03
%S A216752 5,7,13,19,23,29,31,37,43,47,53,61,67,71,73,79,97,101,103,109,113,127,
%T A216752 139,149,151,157,163,167,173,181,191,193,197,199,211,223,229,239,241,
%U A216752 263,269,271,277,281,293,311,313,317,331,337,349,359,367,373,379,383
%N A216752 Primes p such that x^42 = -2 has no solution mod p.
%C A216752 Complement of A051090 relative to A000040.
%H A216752 Vincenzo Librandi, <a href="/A216752/b216752.txt">Table of n, a(n) for n = 1..1000</a>
%t A216752 ok[p_]:=Reduce[Mod[x^42 + 2, p] == 0, x, Integers] == False;Select[Prime[Range[300]], ok] (* _Vincenzo Librandi_, Sep 16 2012 *)
%o A216752 (Magma) [p: p in PrimesUpTo(500) | not exists{x : x in ResidueClassRing(p) | x^42 eq -2} ];
%Y A216752 Cf. A000040, A051090.
%K A216752 nonn,easy
%O A216752 1,1
%A A216752 _Vincenzo Librandi_, Sep 16 2012