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 A161334 #10 Feb 24 2021 02:48:18 %S A161334 0,1,4,7,10,19,22,31,40,49,64,73,88,109,112,121,130,145,172,187,226, %T A161334 247,274,313,334,367,406,415,436,457,484,529,562,625,670,715,766,799, %U A161334 838,883,928,973,1000,1033,1090,1129,1192,1255,1306,1357,1426,1477 %N A161334 Numbers of snowflake sequence, divided by 2: a(n) = A161330(n)/2. %C A161334 Also number of E-toothpicks after n-th stage on the semi-infinite triangular grid. A161332 (the first differences) gives the number of E-toothpicks added at n-th stage. - _Omar E. Pol_, Jan 07 2014 %H A161334 David Applegate, Omar E. Pol and N. J. A. Sloane, <a href="/A000695/a000695_1.pdf">The Toothpick Sequence and Other Sequences from Cellular Automata</a>, Congressus Numerantium, Vol. 206 (2010), 157-191. [There is a typo in Theorem 6: (13) should read u(n) = 4.3^(wt(n-1)-1) for n >= 2.] %H A161334 N. J. A. Sloane, <a href="/A161330/a161330.jpg">A single E-toothpick</a> %H A161334 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> %Y A161334 Cf. A139250, A161328, A161330, A161331, A161332, A161333. %K A161334 nonn %O A161334 0,3 %A A161334 _Omar E. Pol_, Jun 07 2009 %E A161334 More terms from _Omar E. Pol_, Jan 07 2014