%I #9 Feb 24 2021 02:48:18
%S 0,1,2,2,2,4,8,6,6,8,12,8,10,10,20,18,10,16,20,8
%N First differences of A161420.
%C Number of V-toothpicks added at the n-th stage to the V-toothpick structure of A161420. See also A161206 and A161207.
%C Also it appears a(n) is also the number of toothpicks and D-toothpicks added at n-th stage to the H-toothpick structure of A161420. See also A182838 and A182839.
%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>
%H <a href="/index/To#toothpick">Index entries for sequences related to toothpick sequences</a>
%Y Cf. A139251, A161206, A161207, A161420, A161422, A182633, A182838, A182839.
%K more,nonn
%O 0,3
%A _Omar E. Pol_, Jun 10 2009, Dec 12 2010
|