%I #7 Sep 08 2022 08:45:02
%S 311,373,1117,1303,1427,1489,1861,2357,2543,2729,2791,3163,3659,3907,
%T 4093,4217,4651,5023,5147,5209,5333,5519,5581,5953,6263,6449,6883,
%U 7069,7193,7937,8123,8681,8867,8929,9239,9859,10789,11161,11471,11657,11719
%N Primes p such that x^31 = 2 has no solution mod p.
%C Complement of A216883 relative to A000040. - _Vincenzo Librandi_, Sep 20 2012
%H Vincenzo Librandi, <a href="/A059225/b059225.txt">Table of n, a(n) for n = 1..1000</a>
%t ok[p_]:= Reduce[Mod[x^31 - 2, p] == 0, x, Integers] == False; Select[Prime[Range[2000]], ok] (* _Vincenzo Librandi_, Sep 20 2012 *)
%o (Magma) [p: p in PrimesUpTo(12500) | not exists{x : x in ResidueClassRing(p) | x^31 eq 2} ]; // _Vincenzo Librandi_, Sep 20 2012
%Y Cf. A000040, A058853.
%K easy,nonn
%O 1,1
%A _Klaus Brockhaus_, Jan 19 2001