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 A160803 #10 Feb 24 2021 02:48:18 %S A160803 1,2,4,4,4,6,4,3,2,3,4,1,2,3,2,2,4,6,5,3,5,5,2,2,2,2,3,4,3,2,3,4,4,5, %T A160803 8,8,4,1,2,3,3,4,7,8,5,4,7,9,10,15,22,12,7,2,2,3,4,5,6,7,6,5,7,10,13, %U A160803 16,18,9,8,3,3,6,9,8,7 %N A160803 First differences of A160802. %C A160803 Number of toothpicks added to the spiral at the n-th stage. %H A160803 Nathaniel Johnston, <a href="/A160803/b160803.txt">Table of n, a(n) for n = 1..254</a> %H A160803 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 A160803 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 A160803 Cf. A000045, A139250, A139251, A160426, A160427, A160800, A160801, A160802. %K A160803 nonn %O A160803 1,2 %A A160803 _Omar E. Pol_, May 26 2009 %E A160803 Terms after a(12) from _Nathaniel Johnston_, Mar 30 2011