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A161426 Y-toothpick sequence starting at the outside corner of an infinite triangle-shaped polygon as the sieve of A160120 after 2^k rounds. 2
0, 1, 4, 7, 14, 19, 26, 35, 52, 63, 70 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

The sequence gives the number of Y-toothpicks after n rounds. A161427 (the first differences) gives the number added at the n-th round.

See the entries A160120, A139250 and A153006 for more information.

LINKS

Table of n, a(n) for n=0..10.

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

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

David Applegate, The movie version

CROSSREFS

Cf. A000079, A139250, A153006, A160120, A161427, A161830.

Sequence in context: A294016 A049766 A244905 * A115759 A157615 A188319

Adjacent sequences:  A161423 A161424 A161425 * A161427 A161428 A161429

KEYWORD

more,nonn

AUTHOR

Omar E. Pol and David Applegate, Jun 20 2009

STATUS

approved

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Last modified February 22 03:55 EST 2018. Contains 299428 sequences. (Running on oeis4.)