%I #6 Feb 24 2021 02:48:18
%S 0,9,33,57,123,147
%N Fractal triangle whose virtual skeleton is a polyedge as the Y-toothpick structure of A160120.
%C Number of ON states after n generations of cellular automaton based on the infinite triangular grid.
%H 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 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 Cf. A139250, A160120, A161341, A161342, A161343.
%K more,nonn
%O 0,2
%A _Omar E. Pol_, Jun 17 2009
|