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 A059669 #15 Sep 08 2022 08:45:03
%S A059669 1217,1553,1777,2833,4049,4481,5297,6449,6689,7121,8081,8609,9137,
%T A059669 9281,9649,10337,10433,11329,11633,12241,13121,14321,14753,15569,
%U A059669 16433,16673,18257,19793,23057,25169,25889,26177,26561,26993,27281,28001,29153,29201
%N A059669 Primes p such that x^48 = 2 has no solution mod p, but x^24 = 2 has a solution mod p.
%H A059669 Vincenzo Librandi, <a href="/A059669/b059669.txt">Table of n, a(n) for n = 1..188</a>
%t A059669 Select[Prime[Range[PrimePi[30000]]], ! MemberQ[PowerMod[Range[#], 48, #], Mod[2, #]] && MemberQ[PowerMod[Range[#], 24, #], Mod[2, #]] &] (* _Vincenzo Librandi_, Sep 22 2013 *)
%o A059669 (Magma) [p: p in PrimesUpTo(30000) | not exists{x: x in ResidueClassRing(p) | x^48 eq 2} and exists{x: x in ResidueClassRing(p) | x^24 eq 2}]; // _Vincenzo Librandi_, Sep 21 2012
%Y A059669 Cf. A000040, A049556, A059362, A049580.
%K A059669 nonn,easy
%O A059669 1,1
%A A059669 _Klaus Brockhaus_, Feb 04 2001
%E A059669 a(37)-a(38) from _Vincenzo Librandi_, Sep 21 2012