%I #14 Sep 08 2022 08:44:53
%S 2,3,5,7,13,17,19,23,29,37,43,47,53,59,67,73,79,83,89,97,103,107,109,
%T 113,127,137,139,149,157,163,167,173,179,181,193,197,199,223,227,229,
%U 233,239,257,263,269,277,283,293
%N Primes p such that x^5 = 7 has a solution mod p.
%C Complement of A040172 relative to A000040. - _Vincenzo Librandi_, Sep 13 2012
%H Vincenzo Librandi, <a href="/A040171/b040171.txt">Table of n, a(n) for n = 1..1000</a>
%t ok [p_]:= Reduce[Mod[x^5 - 7, p] == 0, x, Integers] =!= False; Select[Prime[Range[150]], ok] (* _Vincenzo Librandi_, Sep 12 2012 *)
%o (Magma) [p: p in PrimesUpTo(300) | exists{x: x in ResidueClassRing(p) | x^5 eq 7}]; // _Vincenzo Librandi_, Sep 12 2012
%Y Cf. A000040, A040172.
%K nonn,easy
%O 1,1
%A _N. J. A. Sloane_