A182842 - OEIS

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A182842

a(n) = A182841(n+2)/2.

2, 4, 7, 8, 7, 12, 19, 16, 7, 12, 23, 32, 27, 28, 43, 32, 7, 12, 23, 32, 31, 40, 63, 72, 43, 28, 55, 84, 79, 72, 99, 64, 7, 12, 23, 32, 31, 40, 63, 72, 47, 40, 71, 112, 119, 112, 143, 152, 75, 28, 55, 84, 91, 108, 163, 204, 151, 88, 131, 204, 207, 180, 219, 128

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

OFFSET

0,1

LINKS

Olaf Voß, Table of n, a(n) for n = 0..998

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

Olaf Voß, Toothpick structures on hexagonal net

Index entries for sequences related to toothpick sequences

EXAMPLE

From Omar E. Pol, Nov 01 2014: (Start)

When written as an irregular triangle with row lengths A011782:

7, 8;

7, 12, 19, 16;

7, 12, 23, 32, 27, 28, 43, 32;

7, 12, 23, 32, 31, 40, 63, 72, 43, 28, 55, 84, 79, 72, 99, 64;

7, 12, 23, 32, 31, 40, 63, 72, 47, 40, 71, 112, 119, 112, 143, 152, 75, 28, 55, 84, 91, 108, 163, 204, 151, 88, 131, 204, 207, 180, 219, 128;

The right border gives the even powers of 2, at least up a(2^9-1).