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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; text; 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, 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 FORMULA a(n) = 4*A160406(n). CROSSREFS Cf. A139250, A139251, A160736, A160738, A160741. Cf. A160170, A160426, A194432, A194434. Sequence in context: A097057 A306219 A160746 * A270345 A181823 A308985 Adjacent sequences:  A160737 A160738 A160739 * A160741 A160742 A160743 KEYWORD nonn AUTHOR Omar E. Pol, May 25 2009 EXTENSIONS More terms from N. J. A. Sloane, May 25 2009 STATUS approved

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Last modified October 18 01:04 EDT 2019. Contains 328135 sequences. (Running on oeis4.)