%I #10 Sep 08 2022 08:46:03
%S 2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,
%T 97,101,103,107,109,113,127,131,137,139,149,151,157,163,167,173,179,
%U 181,191,193,197,199,211,223,227,229,233,239,241,251,257,263,269,271
%N Primes p such that x^47 = 2 has a solution mod p.
%C Complement of A059257 relative to A000040.
%C a(n) = A015919(n+1) up to n=60, and then both sequences start to differ substantially. [_Bruno Berselli_, Sep 20 2012]
%H Vincenzo Librandi, <a href="/A216885/b216885.txt">Table of n, a(n) for n = 1..1000</a>
%t ok[p_] := Reduce[Mod[x^47 - 2, p] == 0, x, Integers] =!= False; Select[Prime[Range[100]], ok]
%o (Magma) [p: p in PrimesUpTo(500) | exists(t){x: x in ResidueClassRing(p) | x^47 eq 2}];
%K nonn,easy
%O 1,1
%A _Vincenzo Librandi_, Sep 20 2012