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 A267698 #11 Apr 02 2016 21:26:31 %S A267698 0,2,6,13,25,32,44,59,79,86,98,113,133,148,176,215,251,258,270,285, %T A267698 305,320,348,387,423,438 %N A267698 Q-toothpick sequence in the first quadrant starting with two Q-toothpicks centered at (1,3) and (3,1) respectively. The endpoints of the left hand Q-toothpick are at (0,3) and (1,4). The endpoints of the right hand Q-toothpick are at (3,0) and (4,1). With a(0) = 0. %C A267698 a(n) is the total number of Q-toothpicks in the structure after n-th stage. %C A267698 A267699 (the first differences) gives the number of Q-toothpicks added at n-th stage. %C A267698 Note that this sequence is also related with the structure and the formula of A187210. For more information see A187210, A267694 and A139250. %H A267698 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 A267698 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a> %H A267698 <a href="/index/To#toothpick">Index entries for sequences related to toothpick sequences</a> %Y A267698 Cf. A139250, A187210, A187220, A267694, A267699. %K A267698 nonn,more %O A267698 0,2 %A A267698 _Omar E. Pol_, Jan 23 2016