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 A151726 #12 Feb 24 2021 02:48:18 %S A151726 0,1,8,4,20,4,20,20,44,4,20,20,44,28,60,76,92,4,20,20,44,28,60,76,92, %T A151726 28,60,84,116,116,196,236,188,4,20,20,44,28,60,76,92,28,60,84,116,116, %U A151726 196,236,188,28,60,84,116,116,196,244,212,116,204,284,348,428 %N A151726 First differences of A151725. %H A151726 David Applegate, <a href="/A151726/b151726.txt">Table of n, a(n) for n = 0..1000</a> %H A151726 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 A151726 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> %H A151726 David Applegate, <a href="/A139250/a139250.anim.html">The movie version</a> %F A151726 For a recurrence see the Applegate-Pol-Sloane paper. %e A151726 May be written as a triangle: %e A151726 0, %e A151726 1, %e A151726 8, %e A151726 4,20, %e A151726 4,20,20,44, %e A151726 4,20,20,44,28,60,76,92, %e A151726 4,20,20,44,28,60,76,92,28,60,84,116,116,196,236,188, %e A151726 4,20,20,44,28,60,76,92,28,60,84,116,116,196,236,188,28,60,84,116,116,196,244,212,116,204,... %e A151726 The rows converge to A151727. %Y A151726 Cf. A151725, A151727-A151729. %Y A151726 Cf. A139251. [From _Omar E. Pol_, Dec 14 2009] %K A151726 nonn,tabf,look %O A151726 0,3 %A A151726 _David Applegate_ and _N. J. A. Sloane_, Jun 13 2009