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 A160425 #6 Feb 24 2021 02:48:18 %S A160425 0,4,10,19,31,40 %N A160425 a(n) = number of grid points that are covered after n-th rounds of A160120. %H A160425 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 A160425 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 A160425 Cf. A139250, A147614, A160120, A160121, A160128. %K A160425 more,nonn %O A160425 0,2 %A A160425 _Omar E. Pol_, Jun 01 2009