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 A170929 #6 Feb 24 2021 02:48:19
%S A170929 1,4,5,3,7,17,17,7,6,13,13,13,32,55,45,15,6,13,13,13,31,51,41,20,25,
%T A170929 39,39,58,120,159,109,31,6,13,13,13,31,51,41,20,25,39,39,58,119,155,
%U A170929 105,36,25,39,39,57,113,143,102,65,89,117,136,236,400,431,253,63,6,13,13,13,31
%N A170929 When regarded as a triangle, the rows of A168131 converge to this sequence.
%H A170929 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 A170929 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>
%F A170929 Sum_{i=0 .. 2^k - 1} a(i) = 4^i - 2^i - 2 for k >= 2 (cf. A170940).
%K A170929 nonn
%O A170929 0,2
%A A170929 _N. J. A. Sloane_, Feb 04 2010