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 A159785 #10 Feb 24 2021 02:48:18 %S A159785 3,6,9,9,12,21,24,15,12,21,27,30,45,66,60,27,12,21,27,30,45,66,63,42, %T A159785 45,69,84,105,156,192,144,51,12,21,27,30,45,66,63,42,45,69,84,105,156, %U A159785 192,147,66,45,69,84,105,156,195,168,129,159,222,273,366,504,528 %N A159785 a(n) = A152980(n)*3. %H A159785 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 A159785 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 A159785 Toothpick sequence: A139250. %Y A159785 Cf. A139251, A147646, A152968, A152978, A152980, A153004, A153006. %K A159785 nonn %O A159785 1,1 %A A159785 _Omar E. Pol_, May 02 2009 %E A159785 More terms from 3*A152980(n) by _Jinyuan Wang_, Mar 14 2020