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 A211974 #16 Sep 26 2015 01:17:13 %S A211974 0,1,1,1,3,1,3,3,3,5,3,5,7,1,3,3,5,9,5,13,7,9,13,7,11,13,3,7,7,9,15, %T A211974 11,21,15,15,17,11,13,15,15,15,9,11,19,13,21,21,17,17,23,17,27,17,19, %U A211974 27,21,27,19,17,17,21,31,31,25,23 %N A211974 Number of E-toothpicks added at n-th stage in the structure of A161336. %C A211974 Essentially the first differences of A161336. %H A211974 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> %H A211974 <a href="/index/To#toothpick">Index entries for sequences related to toothpick sequences</a> %F A211974 a(n) = A161331(n+1)/6, n >= 1. %Y A211974 Cf. A139250, A139251, A161328, A161330, A213360, A211976. %K A211974 nonn %O A211974 0,5 %A A211974 _Omar E. Pol_, Dec 15 2012