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A161421 First differences of A161420. 2
0, 1, 2, 2, 2, 4, 8, 6, 6, 8, 12, 8, 10, 10, 20, 18, 10, 16, 20, 8 (list; graph; refs; listen; history; text; internal format)



Number of V-toothpicks added at the n-th stage to the V-toothpick structure of A161420. See also A161206 and A161207.

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.


Table of n, a(n) for n=0..19.

David Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, 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.]

N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS

Index entries for sequences related to toothpick sequences


Cf. A139251, A161206, A161207, A161420, A161422, A182633, A182838, A182839.

Sequence in context: A286613 A229061 A278224 * A306337 A326022 A077943

Adjacent sequences:  A161418 A161419 A161420 * A161422 A161423 A161424




Omar E. Pol, Jun 10 2009, Dec 12 2010



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Last modified August 6 16:05 EDT 2020. Contains 336255 sequences. (Running on oeis4.)