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A160740 Toothpick sequence starting from a cross formed by 4 toothpicks. 10
0, 4, 8, 16, 24, 32, 40, 56, 72, 80, 88, 104, 120, 136, 160, 200, 232, 240, 248, 264, 280, 296, 320, 360, 392, 408, 432, 472, 512, 560, 640, 744, 808, 816, 824, 840, 856, 872, 896, 936, 968, 984, 1008, 1048, 1088, 1136, 1216, 1320, 1384, 1400, 1424, 1464, 1504, 1552 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

On the infinite square grid we start at stage 0 with no toothpicks. Toothpicks have length 2. At stage 1 we place two consecutive toothpicks in the vertical direction and  two consecutive toothpicks in the horizontal direction forming a cross centered at the origin. At stage 2 we place four toothpicks. At stage 3 we place eight toothpicks. For more information about the toothpick sequences see A139250. - Omar E. Pol, Nov 24 2011

LINKS

David Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, which is also available at arXiv:1004.3036v2

Mathematical Association of America, NumberADay: 1136

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

Index entries for sequences related to toothpick sequences

FORMULA

a(n) = 4*A160406(n).

CROSSREFS

Cf. A139250, A139251, A160736, A160738, A160741.

Cf. A160170, A160426, A194432, A194434.

Sequence in context: A133690 A097057 A160746 * A181823 A046059 A137932

Adjacent sequences:  A160737 A160738 A160739 * A160741 A160742 A160743

KEYWORD

nonn

AUTHOR

Omar E. Pol (info(AT)polprimos.com), May 25 2009

EXTENSIONS

More terms from N. J. A. Sloane, May 25 2009

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Last modified February 15 21:56 EST 2012. Contains 205860 sequences.