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 A160158 #7 Feb 24 2021 02:48:18 %S A160158 0,2,4,8,16,24,28,36,48,56,64,80,104,124,136,156,176,184,192,208,232, %T A160158 252,268,296,328,352,384,440,508,560,600,652,688,696,704,720,744,764, %U A160158 780,808,840,864,896,952,1020,1072,1116,1176,1224,1248,1280,1336,1404 %N A160158 Toothpick sequence starting from a segment of length 4 formed by two toothpicks. %C A160158 The sequence gives the number of toothpicks in the sieve after n-th stage. %H A160158 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 A160158 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 A160158 Cf. A139250, A160406, A160730, A160732, A160736, A160738, A160740. %K A160158 nonn %O A160158 0,2 %A A160158 _Omar E. Pol_, May 29 2009 %E A160158 Extended beyond a(13) by _R. J. Mathar_, Jun 01 2009