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A160128 a(n) = number of grid points that are covered after (2^n)th stage of A139250. 5
3, 7, 19, 63, 235, 919, 3651, 14575, 58267, 233031, 932083, 3728287, 14913099, 59652343, 238609315, 954437199, 3817748731, 15270994855, 61083979347, 244335917311, 977343669163, 3909374676567, 15637498706179 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..22.

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) = A147614(A000079(n)).

a(n) = (1/9)*(2^(2*n+3) + 12*n + 19). [From Nathaniel Johnston, Mar 29 2011]

It appears that a(n) = A139252(2^(n+1)). - Omar E. Pol, Sep 11 2012

CROSSREFS

Cf. A000079, A007583, A139250, A139251, A139252, A139560, A147614.

Sequence in context: A148669 A249380 A210985 * A051139 A049423 A121825

Adjacent sequences:  A160125 A160126 A160127 * A160129 A160130 A160131

KEYWORD

nonn

AUTHOR

Omar E. Pol, May 09 2009

EXTENSIONS

Terms after a(10) from Nathaniel Johnston, Mar 29 2011

STATUS

approved

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Last modified November 22 03:43 EST 2019. Contains 329388 sequences. (Running on oeis4.)