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 A159787 #9 Feb 24 2021 02:48:18 %S A159787 0,0,3,6,6,9,24,36,36,39,48,54,57,78,132,168,168,171,180,186,189,210, %T A159787 252,276,279,294,318,333,360,456,648,720,720,723,732,738,741,762,804, %U A159787 828,831,846,870,885,912,1008,1152,1224,1227,1242 %N A159787 a(n) = A159786(n+1)*3/4. %H A159787 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 A159787 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 A159787 Toothpick sequence: A139250. %Y A159787 Cf. A139251, A153003, A159786, A159788, A159789, A159797. %K A159787 nonn %O A159787 0,3 %A A159787 _Omar E. Pol_, Apr 28 2009, May 02 2009 %E A159787 a(11)-a(49) from _Robert Price_, May 10 2019