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 A160122 #9 Feb 24 2021 02:48:18 %S A160122 2,2,6,2,6,6,14,6,6,6,14,10,14,18,34,18,6,6,14,10,14,18,34,22,14,18, %T A160122 34,34,38,46,78,54,14,6,14,10,14,18,34,22,14,18,34,34,38,46,78,58,22, %U A160122 18,34,34,38,50,86,78,50,46,78,90,94,114,186,154,46,6,14 %N A160122 a(n) = A160121(n+1)*2/3. %H A160122 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 A160122 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 A160122 Y-toothpick sequence: A160120. Cf. A160121, A160123. %Y A160122 Cf. A139250, A139251. [From _Omar E. Pol_, Jun 16 2009] %K A160122 nonn %O A160122 1,1 %A A160122 _Omar E. Pol_, May 02 2009 %E A160122 More terms from _Omar E. Pol_, Jun 16 2009