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A295841 Number of n X 2 0..1 arrays with each 1 adjacent to 1 or 2 king-move neighboring 1s. 1
2, 11, 29, 80, 261, 789, 2354, 7199, 21889, 66280, 201313, 611401, 1855458, 5632611, 17100277, 51909760, 157581005, 478374029, 1452197426, 4408426199, 13382677305, 40625798040, 123327694601, 374385940001, 1136523495202, 3450144328891 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) - a(n-2) + 6*a(n-3) - 8*a(n-4).

Empirical g.f.: x*(1 + 2*x)*(2 + x - 4*x^2) / (1 - 3*x + x^2 - 6*x^3 + 8*x^4). - Colin Barker, Feb 22 2019

EXAMPLE

Some solutions for n=7:

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

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

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

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

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

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

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

CROSSREFS

Column 2 of A295847.

Sequence in context: A009312 A154251 A092275 * A086252 A106926 A220095

Adjacent sequences:  A295838 A295839 A295840 * A295842 A295843 A295844

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 29 2017

STATUS

approved

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Last modified June 28 05:40 EDT 2022. Contains 354903 sequences. (Running on oeis4.)