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A160740
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Toothpick sequence starting from a cross formed by 4 toothpicks.
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10
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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
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OFFSET
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0,2
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COMMENTS
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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
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LINKS
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Table of n, a(n) for n=0..53.
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.], 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
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FORMULA
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a(n) = 4*A160406(n).
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CROSSREFS
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Cf. A139250, A139251, A160736, A160738, A160741.
Cf. A160170, A160426, A194432, A194434.
Sequence in context: A333168 A306219 A160746 * A270345 A335668 A181823
Adjacent sequences: A160737 A160738 A160739 * A160741 A160742 A160743
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KEYWORD
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nonn
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AUTHOR
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Omar E. Pol, May 25 2009
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EXTENSIONS
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More terms from N. J. A. Sloane, May 25 2009
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STATUS
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approved
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