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 A173068 #9 Feb 24 2021 02:48:19 %S A173068 0,0,0,0,0,0,0,0,0,6,6,6,6,6,6,6,6,30,30,30,30,30,30,30,30,42,42,42, %T A173068 42,42,42,42,42,120 %N A173068 a(n) = A160120(n) - A160715(n). %H A173068 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 A173068 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 A173068 Cf. A130665, A139250, A160120, A160715, A173066, A173067, A173451, A173452, A173453. %K A173068 more,nonn %O A173068 0,10 %A A173068 _Omar E. Pol_, May 29 2010 %E A173068 a(14)-a(33) from _Robert Price_, Jun 17 2019