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 A049568 #17 Jul 20 2025 09:26:04
%S A049568 2,23,31,47,71,89,113,127,167,191,223,233,239,257,263,281,311,353,359,
%T A049568 383,431,439,479,503,593,599,601,617,647,719,727,743,839,863,881,887,
%U A049568 911,983,1031,1049,1097,1103,1151,1193,1217,1223,1289,1319,1327,1367
%N A049568 Primes p such that x^36 = 2 has a solution mod p.
%H A049568 R. J. Mathar, <a href="/A049568/b049568.txt">Table of n, a(n) for n = 1..1000</a>
%H A049568 <a href="/index/Pri#smp">Index entries for related sequences</a>
%e A049568 ^36 == 2 (mod 2). 7^36 == 2 (mod 23). 2^36 == 2 (mod 31). 18^36 == 2 (mod 47). 2^36 == 2 (mod 71). 10^36 == 2 (mod 89). 33^36 == 2 (mod 113). 2^36 == 2 (mod 127). 40^36 == 2 (mod 167). - _R. J. Mathar_, Jul 20 2025
%t A049568 ok[p_]:= Reduce[Mod[x^36 - 2, p] == 0, x, Integers] =!= False; Select[Prime[Range[300]], ok] (* _Vincenzo Librandi_, Sep 14 2012 *)
%o A049568 (Magma) [p: p in PrimesUpTo(1500) | exists(t){x : x in ResidueClassRing(p) | x^36 eq 2}]; // _Vincenzo Librandi_, Sep 14 2012
%Y A049568 Cf. A000040.
%K A049568 nonn,easy
%O A049568 1,1
%A A049568 _N. J. A. Sloane_