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%I #4 Sep 15 2012 14:12:01
%S 5,7,11,13,17,23,29,31,37,41,47,53,61,71,79,97,101,103,109,127,131,
%T 137,149,151,157,167,173,181,191,193,197,199,211,223,229,239,241,263,
%U 269,271,277,281,293,311,313,317,331,349,359,367,373,383,389,397,401
%N Primes p such that x^20 = -2 has no solution mod p.
%C Complement of A051079 relative to A000040.
%H Vincenzo Librandi, <a href="/A216741/b216741.txt">Table of n, a(n) for n = 1..1000</a>
%t ok[p_]:= Reduce[Mod[x^20 + 2, p] == 0, x, Integers] == False; Select[Prime[Range[100]], ok]
%Y Cf. A000040, A051079.
%K nonn,easy
%O 1,1
%A _Vincenzo Librandi_, Sep 15 2012