%I
%S 11,31,41,61,71,101,131,151,181,191,251,271,281,331,401,421,431,461,
%T 491,521,571,601,631,641,661,691,701,751,821,881,971,991,1021,1051,
%U 1061,1171,1181,1231,1291,1301,1321
%N Primes p such that x^5 = 15 has no solution mod p.
%C Complement of A040974 relative to A000040.  _Vincenzo Librandi_, Sep 18 2012
%H Vincenzo Librandi, <a href="/A040975/b040975.txt">Table of n, a(n) for n = 1..1000</a>
%t ok[p_]:= Reduce[Mod[x^5  15, p] == 0, x, Integers] == False; Select[Prime[Range[300]], ok] (* _Vincenzo Librandi_, Sep 18 2012 *)
%o (MAGMA) [p: p in PrimesUpTo(1500)  not exists{x : x in ResidueClassRing(p)  x^5 eq 15} ]; // _Vincenzo Librandi_, Sep 18 2012
%K nonn,easy
%O 1,1
%A _N. J. A. Sloane_.
