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A161833 First differences of A161832. 3
1, 1, 2, 1, 2, 2, 4, 2, 2, 2, 4, 3, 4, 5, 9, 5, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Number of Y-toothpicks added to the sieve at the n-th round.

LINKS

Table of n, a(n) for n=1..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

FORMULA

a(n) = A161831(n+1)/2.

CROSSREFS

Cf. A139251, A160121, A160407, A161830, A161831, A161832.

Sequence in context: A122838 A050378 A225216 * A294100 A139318 A205779

Adjacent sequences:  A161830 A161831 A161832 * A161834 A161835 A161836

KEYWORD

more,nonn

AUTHOR

Omar E. Pol, Jun 20 2009

STATUS

approved

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Last modified January 23 13:07 EST 2019. Contains 319393 sequences. (Running on oeis4.)