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A297809 Number of n X 2 0..1 arrays with every element equal to 2 or 3 king-move adjacent elements, with upper left element zero. 7
0, 1, 2, 1, 8, 5, 22, 29, 60, 121, 194, 425, 704, 1421, 2574, 4821, 9156, 16769, 31962, 58977, 111112, 207317, 387366, 726221, 1354508, 2538761, 4741234, 8872857, 16592208, 31023517, 58039870, 108509253, 202982228, 379560465, 709885450 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Column 2 of A297814.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 3*a(n-2) +2*a(n-3) -2*a(n-4).

Empirical g.f.: x^2*(1 + 2*x - 2*x^2) / (1 - 3*x^2 - 2*x^3 + 2*x^4). - Colin Barker, Feb 21 2018

EXAMPLE

Some solutions for n=7:

..0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0

..1..0. .1..0. .0..0. .0..0. .0..0. .0..1. .0..1. .0..0. .0..1. .1..0

..1..1. .1..1. .1..1. .1..1. .1..1. .1..1. .1..1. .1..1. .1..1. .1..1

..1..0. .1..0. .1..1. .0..1. .0..1. .1..0. .0..1. .1..0. .1..0. .1..0

..0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0

..1..1. .0..1. .0..1. .1..0. .1..1. .1..1. .0..1. .1..1. .0..1. .1..0

..1..1. .1..1. .1..1. .1..1. .1..1. .1..1. .1..1. .1..1. .1..1. .1..1

CROSSREFS

Cf. A297814.

Sequence in context: A199468 A337684 A004732 * A160641 A011244 A189966

Adjacent sequences:  A297806 A297807 A297808 * A297810 A297811 A297812

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 06 2018

STATUS

approved

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Last modified June 22 01:02 EDT 2021. Contains 345367 sequences. (Running on oeis4.)