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 A182633 #21 Feb 24 2021 02:48:19 %S A182633 0,3,6,12,12,12,24,36,24,12,24,48,60,48,60,84,48,12,24,48,60,60,84, %T A182633 132,132,72,60,120,168,144,156,192,96,12,24,48,60,60,84,132,132,84,84, %U A182633 156,228,228,228 %N A182633 Number of toothpicks added at n-th stage in the toothpick structure of A182632. %C A182633 First differences of A182632. %C A182633 a(n) is also the number of components added at n-th stage in the toothpick structure formed by V-toothpicks with an initial Y-toothpick, since a V-toothpick has two components and a Y-toothpick has three components (For more information see A161206, A160120, A161644). %H A182633 David Applegate, <a href="/A139250/a139250.anim.html">The movie version</a> %H A182633 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 A182633 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 A182633 <a href="/index/To#toothpick">Index entries for sequences related to toothpick sequences</a> %H A182633 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a> %F A182633 It appears that a(n) = 2*A161645(n) but with a(1)=3. %F A182633 a(n) = 3*A182635(n). - _Omar E. Pol_, Feb 09 2013 %e A182633 From _Omar E. Pol_, Feb 08 2013 (Start): %e A182633 When written as a triangle: %e A182633 0; %e A182633 3; %e A182633 6; %e A182633 12,12; %e A182633 12,24,36,24; %e A182633 12,24,48,60,48,60, 84, 48; %e A182633 12,24,48,60,60,84,132,132,72,60,120,168,144,156,192,96; %e A182633 12,24,48,60,60,84,132,132,84,84,156,228,228,228,... %e A182633 ... %e A182633 It appears that positive terms of the right border are A007283. %e A182633 (End) %Y A182633 A139250, A139251, A160120, A160121, A161206, A161207, A161644, A161645, A182632. %K A182633 nonn,tabf,more %O A182633 0,2 %A A182633 _Omar E. Pol_, Dec 07 2010