

A160126


Total number of squares and rectangles in the toothpick structure after n stages, divided by 2. (See A139250).


4



0, 0, 0, 1, 2, 2, 4, 9, 12, 12, 14, 18, 20, 22, 32, 47, 54, 54, 56, 60, 62, 64, 74, 88, 94, 96, 104, 114, 120, 134, 170, 209, 224, 224, 226, 230, 232, 234, 244, 258, 264, 266, 274, 284, 290, 304, 340, 378, 392, 394, 402, 412, 418, 432, 466, 500, 514
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OFFSET

0,5


LINKS

Table of n, a(n) for n=0..56.
David Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, Congressus Numerantium, Vol. 206 (2010), 157191. [There is a typo in Theorem 6: (13) should read u(n) = 4.3^(wt(n1)1) for n >= 2.]
N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS


FORMULA

a(n) = A160124(n)/2.  Nathaniel Johnston, Apr 12 2011


CROSSREFS

Cf. A139250, A159786, A159787, A159788, A159789, A160124, A160125, A160127.
Sequence in context: A322765 A281605 A199499 * A257515 A105152 A066346
Adjacent sequences: A160123 A160124 A160125 * A160127 A160128 A160129


KEYWORD

nonn


AUTHOR

Omar E. Pol, May 03 2009


EXTENSIONS

Terms beyond a(10) from Nathaniel Johnston, Apr 12 2011


STATUS

approved



