A282371 - OEIS

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A282371

Number of n X 2 0..1 arrays with no 1 equal to more than four of its king-move neighbors, with the exception of exactly two elements.

0, 0, 1, 6, 33, 168, 810, 3780, 17226, 77112, 340443, 1486458, 6431643, 27619056, 117846900, 500088168, 2112085044, 8883220752, 37225117269, 155483824590, 647540441397, 2689724482776, 11145934772190, 46087885526508

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

OFFSET

1,4

LINKS

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

FORMULA

Empirical: a(n) = 6*a(n-1) - 3*a(n-2) - 12*a(n-3) - 27*a(n-4) - 18*a(n-5) - 9*a(n-6).

Empirical g.f.: x^3 / (1 - 3*x - 3*x^2 - 3*x^3)^2. - Colin Barker, Feb 20 2019

EXAMPLE

All solutions for n=4:

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

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

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

CROSSREFS

Column 2 of A282377.

Sequence in context: A099432 A072260 A281930 * A291004 A203155 A084153

Adjacent sequences: A282368 A282369 A282370 * A282372 A282373 A282374

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 13 2017

STATUS

approved