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 A020140 #19 Jun 13 2018 03:43:11
%S A020140 65,91,133,143,145,247,377,385,703,1045,1099,1105,1649,1729,1885,1891,
%T A020140 2041,2233,2465,2701,2821,2983,3367,3553,5005,5365,5551,5785,6061,
%U A020140 6305,6601,8911,9073,10585,11077,12403,12673,12905,13051,13333,13345,13585
%N A020140 Pseudoprimes to base 12.
%C A020140 Composite numbers n such that 12^(n-1) == 1 (mod n). - _Michel Lagneau_, Feb 18 2012
%H A020140 T. D. Noe, <a href="/A020140/b020140.txt">Table of n, a(n) for n = 1..1000</a>
%H A020140 <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a>
%t A020140 base = 12; 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 A020140 Cf. A001567 (pseudoprimes to base 2).
%K A020140 nonn
%O A020140 1,1
%A A020140 _David W. Wilson_