A160731 First differences of A160730.

2, 2, 4, 6, 6, 6, 12, 14, 12, 6, 12, 14, 16, 18, 32, 34, 20, 6, 12, 14, 16, 18, 32, 34, 24, 18, 32, 38, 44, 62, 92, 82, 36, 6, 12, 14, 16, 18, 32, 34, 24, 18, 32, 38, 44, 62, 92, 82, 40, 18, 32, 38, 44, 62

Offset

1,1

Links

Table of n, a(n) for n=1..54.

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

From Nathaniel Johnston, Mar 28 2011: (Start)

a(n) = 2*A168113(n)

a(2^(n+2) + 1) = 4(2^n + 1), n >= 1.

(End)

Example

Placing the entries starting from a(4) in a triangle with rows that have length equal to powers of two gives:
6, 6
6, 12, 14, 12
6, 12, 14, 16, 18, 32, 34, 20
6, 12, 14, 16, 18, 32, 34, 24, 18, 32, 38, 44, 62, 92, 82, 36
...
The rows of this triangle tend to 2*A168114.

Crossrefs

Cf. A139250, A139251, A160730, A160733, A160737, A160739, A160741.

Sequence in context: A075569 A338276 A062722 * A323647 A302928 A098214

Adjacent sequences: A160728 A160729 A160730 * A160732 A160733 A160734

Keyword

nonn

Author

Omar E. Pol, May 25 2009

Extensions

Terms after a(11) from Nathaniel Johnston, Mar 28 2011

Status

approved