This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A040136 #12 Jul 08 2025 22:50:48
%S A040136 13,17,19,23,29,31,37,41,47,73,79,83,89,97,101,107,139,149,151,157,
%T A040136 167,173,193,197,199,211,227,229,233,263,269,271,277,281,293,313,331,
%U A040136 337,347,353,373,379,383,389,397
%N A040136 Primes p such that x^4 = 15 has no solution mod p.
%C A040136 Complement of A040130 relative to A000040. - _Vincenzo Librandi_, Sep 18 2012
%H A040136 Vincenzo Librandi, <a href="/A040136/b040136.txt">Table of n, a(n) for n = 1..1000</a>
%t A040136 ok[p_]:= Reduce[Mod[x^4 - 15, p] == 0, x, Integers] == False; Select[Prime[Range[100]], ok] (* _Vincenzo Librandi_, Sep 18 2012 *)
%o A040136 (Magma) [p: p in PrimesUpTo(500) | not exists{x : x in ResidueClassRing(p) | x^4 eq 15} ]; // _Vincenzo Librandi_, Sep 18 2012
%o A040136 (PARI) is(n)=isprime(n) && !ispower(Mod(15,n),4) \\ _Charles R Greathouse IV_, Feb 23 2017
%K A040136 nonn,easy
%O A040136 1,1
%A A040136 _N. J. A. Sloane_