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A161832 a(n) = (A161830(n+1)-1)/2. 3
0, 1, 2, 4, 5, 7, 9, 13, 15, 17, 19, 23, 26, 30, 35, 44, 49, 51 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

The sequence gives the number of Y-toothpicks in the structure after n rounds. A161833 (the first differences) gives the number added at the n-th round.

See the Y-toothpick sequence A160120 and A161830 for more information.

LINKS

Table of n, a(n) for n=0..17.

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

CROSSREFS

Cf. A139250, A160120, A160406, A161830, A161831, A161833.

Sequence in context: A249058 A105771 A193494 * A078404 A056908 A296344

Adjacent sequences:  A161829 A161830 A161831 * A161833 A161834 A161835

KEYWORD

more,nonn

AUTHOR

Omar E. Pol, Jun 20 2009

STATUS

approved

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Last modified January 17 17:23 EST 2019. Contains 319250 sequences. (Running on oeis4.)