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