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 A151673 #10 Feb 24 2021 02:48:18
%S A151673 1,4,0,0,4,16,0,0,0,0,0,0,0,0,0,0,4,16,0,0,16,64,0,0,0,0,0,0,0,0,0,0,
%T A151673 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,4,16,
%U A151673 0,0,16,64,0,0,0,0,0,0,0,0,0,0,16,64,0,0,64,256,0,0,0,0,0,0,0,0,0,0,0,0,0,0
%N A151673 G.f.: Product_{k>=0} (1 + 4*x^(4^k)).
%H A151673 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 A151673 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 A151673 For generating functions Product_{k>=0} (1 + a*x^(b^k)) for the following values of (a,b) see: (1,2) A000012 and A000027, (1,3) A039966 and A005836, (1,4) A151666 and A000695, (1,5) A151667 and A033042, (2,2) A001316, (2,3) A151668, (2,4) A151669, (2,5) A151670, (3,2) A048883, (3,3) A117940, (3,4) A151665, (3,5) A151671, (4,2) A102376, (4,3) A151672, (4,4) A151673, (4,5) A151674.
%K A151673 nonn
%O A151673 0,2
%A A151673 _N. J. A. Sloane_, May 30 2009