A216887 - OEIS

%I #18 Sep 08 2022 08:46:04

%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 181,191,193,197,199,211,223,227,229,233,239,241,251,257,263,271

%N Primes p such that x^67 = 2 has a solution mod p.

%C Complement of A059330 relative to A000040.

%H Vincenzo Librandi, <a href="/A216887/b216887.txt">Table of n, a(n) for n = 1..1000</a>

%t ok[p_] := Reduce[Mod[x^67 - 2, p] == 0, x, Integers] =!= False; Select[Prime[Range[60]], ok]

%o (Magma) [p: p in PrimesUpTo(500) | exists{x: x in ResidueClassRing(p) | x^67 eq 2}];

%Y Cf. A000040, A059330.

%K nonn,easy

%O 1,1

%A _Vincenzo Librandi_, Sep 20 2012