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 A233781 #18 Dec 22 2013 00:03:41 %S A233781 0,1,2,2,4,2,4,6,8,2,4,6,10,10,8,14,16,2,4,6,10,10,10,18,24,18,8,14, %T A233781 22,26,16,30,32,2,4,6,10,10,10,18,24,18,10,18,30,38,26,42,52,34,8,14, %U A233781 22,26,22,42,56,50,16,30,46,58,32,62,64,2,4,6,10,10 %N A233781 Number of toothpicks or D-toothpicks added at n-th stage to the structure of the D-toothpick "wide" triangle of A233780. %C A233781 Essentially the first differences of A233780. %C A233781 First differs from A170905 at a(24). %C A233781 First differs from A233971 at a(25). %C A233781 First differs from A233765 at a(44). %H A233781 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 A233781 <a href="/index/To#toothpick">Index entries for sequences related to toothpick sequences</a> %e A233781 Written as an irregular triangle in which the row lengths is A011782 the sequence (starting from 1) begins: %e A233781 1; %e A233781 2; %e A233781 2,4; %e A233781 2,4,6,8; %e A233781 2,4,6,10,10,8,14,16; %e A233781 2,4,6,10,10,10,18,24,18,8,14,22,26,16,30,32; %e A233781 2,4,6,10,10,10,18,24,18,10,18,30,38,26,42,52,34,8,14,22,26,22,42,56,50,16,30,46,58,32,62,64; %e A233781 Right border gives A000079. %Y A233781 Cf. A000079, A011782, A139251, A170905, A220501, A220521, A231349, A233765, A233780, A233782, A233971. %K A233781 nonn,tabf %O A233781 0,3 %A A233781 _Omar E. Pol_, Dec 15 2013