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 A192450 #18 Feb 11 2021 01:21:13
%S A192450 3,4,6,7,8,9,11,12,14,15,16,18,19,20,21,22,23,24,27,28,30,31,32,33,35,
%T A192450 36,38,39,40,42,43,44,45,46,47,48,49,51,52,54,55,56,57,59,60,62,63,64,
%U A192450 66,67,68,69,70,71,72,75,76,77,78,79,80,81,83,84,86,87,88,90,91,92,93,94,95,96,98,99,100,102,103,104,105,107,108
%N A192450 Numbers k such that -1 is not a square mod k.
%C A192450 Contains A002145 as a subsequence.
%C A192450 Numbers that are divisible by 4 or by a term of A002145. - _Robert Israel_, May 14 2020
%H A192450 Robert Israel, <a href="/A192450/b192450.txt">Table of n, a(n) for n = 1..10000</a>
%p A192450 filter:= n -> n mod 4 = 0 or member(3, numtheory:-factorset(n) mod 4):
%p A192450 select(filter, [$1..1000]); # _Robert Israel_, May 14 2020
%t A192450 Table[If[Reduce[x^2==-1,Modulus->n]===False,n],{n,2,200}]//Union
%o A192450 (PARI) for(n=1, 1e3, if(!issquare(Mod(-1, n)), print1(n", "))) \\ _Charles R Greathouse IV_, Jul 04 2011
%Y A192450 Cf. A008784, A002145, A334819.
%K A192450 nonn
%O A192450 1,1
%A A192450 _José María Grau Ribas_, Jul 01 2011