%I #12 Sep 08 2022 08:44:53
%S 7,13,31,37,43,61,67,73,79,103,139,157,163,193,199,211,223,229,241,
%T 331,337,349,367,379,397,433,439,457,463,499,523,541,547,571,601,607,
%U 619,631,643,673,709,727,739,751
%N Primes p such that x^3 = 19 has no solution mod p.
%C Complement of A040083 relative to A000040. - _Vincenzo Librandi_, Sep 17 2012
%H Vincenzo Librandi, <a href="/A040084/b040084.txt">Table of n, a(n) for n = 1..1000</a>
%t ok[p_]:= Reduce[Mod[x^3 - 19, p] == 0, x, Integers] == False;Select[Prime[Range[200]], ok] (* _Vincenzo Librandi_, Sep 17 2012 *)
%o (Magma) [p: p in PrimesUpTo(1000) | not exists{x : x in ResidueClassRing(p) | x^3 eq 19} ]; // _Vincenzo Librandi_, Sep 17 2012
%K nonn,easy
%O 1,1
%A _N. J. A. Sloane_.