A160126 Total number of squares and rectangles in the toothpick structure after n stages, divided by 2. (See A139250).

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

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

Crossrefs

Cf. A139250, A159786, A159787, A159788, A159789, A160124, A160125, A160127.

Sequence in context: A281605 A199499 A351351 * 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