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 A172312 #9 Feb 24 2021 02:48:19 %S A172312 1,2,3,4,6,7,7,9,9,10,12,12,19,17,21,17,13,14,16,19,25,27,29,29,33,30, %T A172312 28,25,33,33,33,35,21,26,28,27,31,33,39,44 %N A172312 a(n) = A172311(n+1)/2. %H A172312 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 A172312 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 A172312 Cf. A139250, A139251, A172310, A172311. %K A172312 nonn %O A172312 1,2 %A A172312 _Omar E. Pol_, Jan 31 2010 %E A172312 More terms from _Nathaniel Johnston_, Nov 15 2010