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A152978 a(n) = A139251(n+2)/4 = A152968(n+1)/2. 23
1, 1, 1, 2, 3, 2, 1, 2, 3, 3, 4, 7, 8, 4, 1, 2, 3, 3, 4, 7, 8, 5, 4, 7, 9, 10, 15, 22, 20, 8, 1, 2, 3, 3, 4, 7, 8, 5, 4, 7, 9, 10, 15, 22, 20, 9, 4, 7, 9, 10, 15, 22, 21, 14, 15, 23, 28, 35, 52, 64, 48, 16, 1, 2, 3, 3, 4, 7, 8, 5, 4, 7, 9, 10, 15, 22, 20, 9, 4, 7, 9, 10, 15, 22, 21, 14, 15, 23 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Also, first differences of toothpick numbers A153000.

LINKS

Table of n, a(n) for n=1..88.

David Applegate, The movie version

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

FORMULA

G.f.: (1+x)*(Prod(1+x^(2^k-1)+2*x^(2^k),k=1..oo)-1)/(1+2*x). - N. J. A. Sloane, May 20 2009

EXAMPLE

If written as a triangle, begins:

.1,1;

.1,2,3,2;

.1,2,3,3,4,7,8,4;

.1,2,3,3,4,7,8,5,4,7,9,10,15,22,20,8;

....

Rows converge to A152980.

It appears that row sums give A004171. [From Omar E. Pol, May 25 2010]

CROSSREFS

Cf. toothpick sequence A139250.

Cf. A139251, A139252, A139560, A152968, A152973.

Cf. A152980, A152998, A153000, A153001, A153003, A153004, A153006.

Cf. A004171. [From Omar E. Pol, May 25 2010]

Sequence in context: A030314 A269624 A098236 * A118121 A006968 A058207

Adjacent sequences:  A152975 A152976 A152977 * A152979 A152980 A152981

KEYWORD

nonn,easy

AUTHOR

Omar E. Pol, Dec 16 2008, Dec 20 2008

EXTENSIONS

More terms from Omar E. Pol, Jul 26 2009

STATUS

approved

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Last modified November 19 01:27 EST 2017. Contains 294912 sequences.