



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
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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^k1)+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



