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 A151836 #14 Feb 24 2021 02:48:18 %S A151836 1,4,4,12,4,12,12,28,4,12,12,28,20,28,36,68,4,12,12,28,20,28,36,68,36, %T A151836 28,36,68,68,76,100,172,12,28,12,28,20,28,36,68,36,28,36,68,68,76,100, %U A151836 172,76,28,36,68,68,76 %N A151836 First differences of A147552. %H A151836 David Applegate, Omar E. Pol and N. J. A. Sloane, <a href="/A000695/a000695_1.pdf">The Toothpick Sequence and Other Sequences from Cellular Automata</a>, Congressus Numerantium, Vol. 206 (2010), 157-191. [There is a typo in Theorem 6: (13) should read u(n) = 4.3^(wt(n-1)-1) for n >= 2.] %H A151836 N. J. A. Sloane, <a href="/wiki/Catalog_of_Toothpick_and_CA_Sequences_in_OEIS">Catalog of Toothpick and Cellular Automata Sequences in the OEIS</a> %Y A151836 Cf. A139250, A147552, A151837, A160721. %K A151836 nonn %O A151836 1,2 %A A151836 _N. J. A. Sloane_, Jul 13 2009 %E A151836 Terms after a(30) from _Nathaniel Johnston_, Mar 27 2011