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 A233762 #9 Dec 19 2013 11:44:01 %S A233762 0,1,3,5,9,11,15,20,28,30,34,40,52,58,64,75,91,93,97,103,115,129,145, %T A233762 163,187,197,205,219,247,261,277,300,332,334,338,344,356,370,386,406, %U A233762 438,464,484,506,546,576,616,655,703,721,729 %N A233762 Number of toothpicks and D-toothpicks after n-th stage in the D-toothpick "narrow" triangle of the third kind, second version. %C A233762 The structure is essentially the same as A220522 but here the borders do not contain D-toothpicks with exposed endpoints except the initial D-toothpick. The structure is one of the oblique wedges of several D-toothpick structures. For more information see A220500. The first differences (A233763) give the number of toothpicks or D-toothpicks added at n-th stage. %H A233762 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 A233762 <a href="/index/To#toothpick">Index entries for sequences related to toothpick sequences</a> %Y A233762 Cf. A139250, A220500, A220522, A233760, A233763. %K A233762 nonn %O A233762 0,3 %A A233762 _Omar E. Pol_, Dec 15 2013