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 A020228 #34 Aug 28 2022 05:21:37
%S A020228 9,33,91,99,153,259,303,451,481,561,657,703,909,949,1111,1233,1241,
%T A020228 1729,1891,2047,2329,2409,2701,2821,2871,2981,3333,3367,4141,4187,
%U A020228 4521,5461,5551,6001,6533,6541,6601,6931,7107,7373,7471,7633,7777,8149,8401,8911
%N A020228 Pseudoprimes to base 100.
%C A020228 Composite numbers n such that 100^(n-1) == 1 (mod n). - _Michel Lagneau_, Feb 18 2012
%H A020228 T. D. Noe, <a href="/A020228/b020228.txt">Table of n, a(n) for n = 1..1000</a>
%H A020228 <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a>
%t A020228 base = 100; t = {}; n = 1; While[Length[t] < 100, n++; If[! PrimeQ[n] && PowerMod[base, n-1, n] == 1, AppendTo[t, n]]]; t (* _T. D. Noe_, Feb 21 2012 *)
%Y A020228 Cf. A001567 (pseudoprimes to base 2).
%K A020228 nonn
%O A020228 1,1
%A A020228 _David W. Wilson_