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 A168115 #9 Feb 24 2021 02:48:19 %S A168115 1,1,1,2,2,1,1,2,2,2,4,6,4,1,1,2,2,2,4,6,4,2,4,6,6,8,14,16,8,1,1,2,2, %T A168115 2,4,6,4,2,4,6,6,8,14,16,8,2,4,6,6,8,14,16,10,8,14,18,20,30,44,40,16, %U A168115 1,1,2,2,2,4,6,4,2,4,6,6,8,14,16 %N A168115 a(n) = A139560(n+1)/2. %H A168115 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 A168115 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 A168115 Cf. A139250, A139252, A139560. %K A168115 nonn %O A168115 1,4 %A A168115 _Omar E. Pol_, Dec 09 2009 %E A168115 Terms after a(27) from _Nathaniel Johnston_, Mar 29 2011