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 A267191 #15 Jan 30 2016 18:16:52 %S A267191 1,4,4,4,12,4,12,12,12,20,12,20,28,4,12,12,20,28,20,36,36,44,44,36,52, %T A267191 52,12,28,28,36,44,44,68,68,76,76,60,68,68,60,68,52,36,68,68,84,100, %U A267191 76,76,92,60,84,84,92,132,100,132,116,92,76,76,108,140,100,100,100,132,92,156,172,108,76,108,108,124,164,140,148,132,116,108,172,148,108,100 %N A267191 Number of new cells turned ON at generation n in cellular automaton described in A267190. %C A267191 First differences of A267190, which has much more information. %H A267191 David Applegate, <a href="/A267191/b267191.txt">Table of n, a(n) for n = 1..260</a> %H A267191 David Applegate, <a href="/A139250/a139250.anim.html">The movie version</a> %Y A267191 Cf. A267190. %K A267191 nonn %O A267191 1,2 %A A267191 _David Applegate_ and _N. J. A. Sloane_, Jan 21 2016 %E A267191 Corrected by _David Applegate_, Jan 30 2016