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A160731 First differences of A160730. 4
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified June 14 10:04 EDT 2021. Contains 345025 sequences. (Running on oeis4.)