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 A028813 #50 Dec 26 2019 04:45:48
%S A028813 2,3,5,6,7,8,10,11,12,13,14,15,17,18,19,20,22,23,26,27,28,30,31,32,33,
%T A028813 34,35,37,38,39,40,42,43,45,46,47,48,50,51,52,53,54,55,57,58,59,60,62,
%U A028813 63,65,66,67,68,70,71,72,73,74,75,77,78,79,80,82,83,85,86,87,88,90,91,92,93,94,95,97,98,99
%N A028813 Nonsquares mod 100.
%C A028813 Complement of A010461. Numbers n such that k^2 == n (mod 100) has no solution. - _Altug Alkan_, Dec 10 2015
%t A028813 n = 100; Complement[Range[0, n - 1], Union@ Array[PowerMod[#, 2, n] &, {100}]] (* _Michael De Vlieger_, Dec 10 2015 *)
%o A028813 (PARI) v=vector(100,n,n^2%100); v=vecsort(v); for(i=1, 99, if (!vecsearch(v,i), print1(i,", "))) \\ _Derek Orr_, Sep 25 2014
%o A028813 (PARI) for (n=0, 99, if (!issquare(Mod(n, 100)), print1(n, ", "));); \\ _Michel Marcus_, Dec 10 2015
%o A028813 (Scala) (0 to 99).diff((1 to 100).map(n => (n * n) % 100)) // _Alonso del Arte_, Dec 25 2019
%Y A028813 Cf. A000037 (nonsquares).
%Y A028813 Cf. A010461.
%K A028813 nonn,fini,full,easy
%O A028813 1,1
%A A028813 _N. J. A. Sloane_
%E A028813 More terms to show full sequence from _Derek Orr_, Sep 25 2014