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 A172313 #9 Feb 24 2021 02:48:19 %S A172313 1,1,1,2,2,1,2,3,3,4,3,6,5,3,2,3,5,6,5,7,7,8,8,9,7,8,6,10,11,4,4,8,9, %T A172313 8,5,8,10,12,13,18,12,16,15,20,14,12 %N A172313 a(n) = A172309(n+1)/2. %H A172313 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 A172313 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 A172313 Cf. A139250, A172304, A172305, A172306, A172307, A172308, A172309, A172310, A172311, A172312. %K A172313 more,nonn %O A172313 1,4 %A A172313 _Omar E. Pol_, Feb 06 2010 %E A172313 a(16)-a(46) from _Robert Price_, Jun 17 2019