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 A187221 First differences of A187220. 5
 0, 1, 2, 4, 8, 8, 8, 16, 24, 16, 8, 16, 24, 24, 32, 56, 64, 32, 8, 16, 24, 24, 32, 56, 64, 40, 32, 56, 72, 80, 120, 176, 160, 64, 8, 16, 24, 24, 32, 56, 64, 40, 32, 56, 72, 80, 120, 176, 160, 72, 32, 56, 72, 80, 120, 176, 168, 112, 120, 184, 224, 280, 416, 512, 384, 128, 8 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Number of gulls (or G-toothpicks) added at n-th stage to the gullwing structure of A187220. Apparently this is the connection between A147582 and A139251. - Omar E. Pol, Mar 11 2011 LINKS David Applegate, The movie version 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.] N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS FORMULA a(0)=0. a(1)=1. It appears that a(n) = 2*A139251(n-1), for n >= 2. EXAMPLE If written as an irregular triangle begins: 0, 1, 2, 4, 8,8, 8,16,24,16, 8,16,24,24,32,56,64,32, 8,16,24,24,32,56,64,40,32,56,72,80,120,176,160,64, ... Also there is another version in which the layout of the irregular triangle was adjusted to reveal that the columns become constant: .0, .1, .2, .4,8, .8,8,16,24, 16,8,16,24,24,32,56,64, 32,8,16,24,24,32,56,64,40,32,56,72,80,120,176,160, 64,8,16,24,24,32,56,64,40,32,56,72,80,120,176,160,72,32,56,72,80... CROSSREFS Cf. A139250, A139251, A147582, A187211, A187220. Sequence in context: A178573 A162794 A172305 * A129280 A103224 A198346 Adjacent sequences:  A187218 A187219 A187220 * A187222 A187223 A187224 KEYWORD nonn AUTHOR Omar E. Pol, Mar 07 2011, Mar 09 2011 STATUS approved

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Last modified January 17 16:50 EST 2019. Contains 319235 sequences. (Running on oeis4.)