A151885 Similar to the original toothpick sequence A139250, except that the rule is now: a toothpick changes state if its midpoint is adjacent to exactly one ON toothpick.

0, 1, 3, 5, 11, 5, 15, 17, 39, 5, 15, 25, 55, 17, 51, 61, 139, 5, 15, 25, 55, 25, 75, 85, 195, 17, 51, 85, 187, 61, 183, 217, 495, 5, 15, 25, 55, 25, 75, 85, 195, 25, 75, 125, 275, 85, 255, 305, 695, 17, 51, 85, 187, 85, 255, 289, 663

Offset

0,3

Comments

In the original toothpick sequence A139250, a toothpick simply turned ON (and stayed ON) if its midpoint was adjacent to exactly one ON toothpick.

Related to A139250 in the same way that A079315 is related to A147562.

Links

Nathaniel Johnston, Table of n, a(n) for n = 0..925

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.]

Nathaniel Johnston, C program for computing terms of A151885-A151888

N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS

N. J. A. Sloane, Illustration of first 8 generations

Formula

a(n) = a(n-1) + A151888(n).

Crossrefs

Cf. A151886-A151888, A139250, A139251, A147562, A079314, A079315.

Sequence in context: A139430 A143386 A214862 * A137656 A046228 A132162

Adjacent sequences: A151882 A151883 A151884 * A151886 A151887 A151888

Keyword

nonn

Author

N. J. A. Sloane, Jul 23 2009

Extensions

Terms after a(8) from Nathaniel Johnston, Apr 02 2011

Status

approved