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 A294960 #33 Apr 16 2018 09:08:52 %S A294960 0,2,8,14,20,26,44,50,68,86,104,110,128,158,176,206,260,278,320,350, %T A294960 392,410,452,494,548,614 %N A294960 Snowflake (or E-toothpick) sequence of the second kind (see Comments lines for definition). %C A294960 This has essentially the same rules as the snowflake sequence A161330, but here there is an additional rule: there are no E-toothpicks of the same generation that share the endpoint of two parallel components. %C A294960 The structure is lighter than the structure of A161330 from which differs at a(7). %C A294960 Note that, on the infinite triangular grid, an E-toothpick can be represented as a polyedge with three components. In this case, at the n-th round, the structure is a polyedge with 3*a(n) components. %C A294960 An E-toothpick looks like a bird's footprint (or more generally a dinosaur's footprint). %C A294960 a(n) gives the number of E-toothpicks in the structure after n rounds. %C A294960 A294961(n) is the number of E-toothpicks added at the n-th round, n >= 1. - _Omar E. Pol_, Apr 15 2018 %H A294960 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 A294960 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a> %H A294960 <a href="/index/To#toothpick">Index entries for sequences related to toothpick sequences</a> %Y A294960 Another version of A161330. %Y A294960 Cf. A139250, A160120, A161328, A294961 (first differences). %K A294960 nonn,more %O A294960 0,2 %A A294960 _Omar E. Pol_, Nov 12 2017