A139560 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

A139560

Number of new segments added to the toothpick structure drawing at the n-th step (extensions of earlier segments are not considered).

6

1, 2, 2, 2, 4, 4, 2, 2, 4, 4, 4, 8, 12, 8, 2, 2, 4, 4, 4, 8, 12, 8, 4, 8, 12, 12, 16, 28, 32, 16, 2, 2, 4, 4, 4, 8, 12, 8, 4, 8, 12, 12, 16, 28, 32, 16, 4, 8, 12, 12, 16, 28, 32, 20, 16, 28, 36, 40, 60, 88, 80, 32

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

First differences of A139252.

LINKS

Table of n, a(n) for n=1..62.

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)=A139252(n)-A139252(n-1).

CROSSREFS

Cf. A139250, A139251, A139252, A139253, A139254, A139559.

Sequence in context: A064135 A332476 A179651 * A192095 A363710 A105080

Adjacent sequences: A139557 A139558 A139559 * A139561 A139562 A139563

KEYWORD

nonn

AUTHOR

Omar E. Pol, May 17 2008

EXTENSIONS

Terms after a(28) from Nathaniel Johnston, Mar 29 2011

STATUS

approved