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A151710 First differences of A160715. 7
1, 3, 3, 9, 3, 9, 9, 21, 3, 9, 9, 21, 15, 21, 27, 51, 3, 9, 9, 21, 15, 21, 27, 51, 21, 21, 27, 51 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Number of Y-toothpick added at n-th stage to the structure of A160715.

Similar to A160121. [From Omar E. Pol, May 29 2010]

LINKS

Table of n, a(n) for n=1..28.

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

EXAMPLE

Contribution from Omar E. Pol, Dec 18 2012 (Start):

Written as an irregular triangle begins:

1;

3;

3, 9;

3, 9, 9, 21;

3, 9, 9, 21, 15, 21, 27, 51;

3, 9, 9, 21, 15, 21, 27, 51, 21, 21, 27, 51,...

(End)

CROSSREFS

Cf. A000225, A006516, A139250, A160120.

Cf. A048883, A139251, A151837, A160121.

Sequence in context: A165824 A256689 A266533 * A160121 A048883 A241717

Adjacent sequences:  A151707 A151708 A151709 * A151711 A151712 A151713

KEYWORD

more,nonn

AUTHOR

Omar E. Pol, Jun 02 2009

EXTENSIONS

More terms from Omar E. Pol, May 29 2010

STATUS

approved

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Last modified January 21 17:38 EST 2019. Contains 319350 sequences. (Running on oeis4.)