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 A159794 #9 Feb 24 2021 02:48:18 %S A159794 0,3,9,18,27,39,60,84,99,111,132,159,189,234,300,360,387,399,420,447, %T A159794 477,522,588,651,693,738,807,891,996,1152,1344,1488,1539,1551,1572, %U A159794 1599,1629,1674,1740,1803,1845,1890,1959,2043,2148,2304,2496,2643 %N A159794 a(n) = A153006(n)*3. %H A159794 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 A159794 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 A159794 Toothpick sequence: A139250. %Y A159794 Cf. A139251, A152980, A153006, A159793, A159795. %K A159794 nonn %O A159794 0,2 %A A159794 _Omar E. Pol_, May 02 2009 %E A159794 More terms from _Max Alekseyev_, Dec 13 2011