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 A161216 #6 Feb 24 2021 02:48:18 %S A161216 0,4,12,28,56,84,112 %N A161216 a(n) = A161210(n)*4. %H A161216 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 A161216 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 A161216 Cf. A139250, A152980, A153006, A160160, A161210, A161212, A161214, A161217. %K A161216 more,nonn %O A161216 0,2 %A A161216 _Omar E. Pol_, Jun 06 2009