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A296733 Number of n X 2 0..1 arrays with each 1 adjacent to 1, 2 or 4 king-move neighboring 1s. 1
2, 11, 31, 88, 287, 881, 2686, 8347, 25763, 79376, 245227, 757045, 2336222, 7212287, 22263871, 68722504, 212138639, 654844841, 2021399374, 6239772643, 19261292171, 59456768000, 183534426499, 566544237805, 1748839677662, 5398414303799 (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) + 8*a(n-3) - 12*a(n-4) + 2*a(n-5) - 12*a(n-6).

Empirical g.f.: x*(2 + x + 2*x^2)*(1 + 2*x - 2*x^2 - 6*x^3) / (1 - 3*x + x^2 - 8*x^3 + 12*x^4 - 2*x^5 + 12*x^6). - Colin Barker, Feb 25 2019

EXAMPLE

Some solutions for n=5:

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

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

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

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

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

CROSSREFS

Column 2 of A296739.

Sequence in context: A121346 A106847 A092761 * A087933 A190259 A190261

Adjacent sequences:  A296730 A296731 A296732 * A296734 A296735 A296736

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 19 2017

STATUS

approved

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Last modified June 26 04:11 EDT 2019. Contains 324369 sequences. (Running on oeis4.)