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 A173532 #6 Feb 24 2021 02:48:19 %S A173532 0,0,0,0,0,0,0,4,0,0,0,4,4,0,4,32,0,0,0,4,4,0,4,32,12,0,4,28,24,4,40, %T A173532 176,0,0,0,4,4,0,4,32,12,0,4,28,24,4,40,176,28,0,4,28,24,4,40,172,72, %U A173532 4,36,144,116,48,256,832,0,0,0,4,4,0,4,32,12,0,4 %N A173532 a(n) = A173531(n) - A139251(n). %H A173532 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 A173532 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> %e A173532 If written as a triangle, begins: %e A173532 0; %e A173532 0; %e A173532 0,0; %e A173532 0,0,0,4; %e A173532 0,0,0,4,4,0,4,32; %e A173532 0,0,0,4,4,0,4,32,12,0,4,28,24,4,40,176; %e A173532 0,0,0,4,4,0,4,32,12,0,4,28,24,4,40,176,28,0,4,28,24,4,40,172,72,4,36,144,116,48,256,832; %Y A173532 Cf. A139250, A139251, A161207, A172311, A173530, A173531. %K A173532 nonn %O A173532 0,8 %A A173532 _Omar E. Pol_, Oct 10 2010