A269083 - OEIS

A269083

Number of n X 2 binary arrays with some element plus some horizontally, vertically or antidiagonally adjacent neighbor totalling two not more than once.

4, 11, 30, 76, 191, 467, 1127, 2686, 6339, 14840, 34504, 79759, 183445, 420077, 958248, 2178427, 4937234, 11159252, 25160111, 56599879, 127066227, 284728994, 636922003, 1422499564, 3172350160, 7065116255, 15714769641, 34912773337

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OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) + 3*a(n-2) - 2*a(n-3) - 6*a(n-4) - 4*a(n-5) - a(n-6).

Empirical g.f.: x*(4 + 3*x - 4*x^2 - 9*x^3 - 5*x^4 - x^5) / (1 - x - 2*x^2 - x^3)^2. - Colin Barker, Jan 19 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 2 of A269089.

Sequence in context: A099065 A296262 A102281 * A026583 A339739 A291238

Adjacent sequences: A269080 A269081 A269082 * A269084 A269085 A269086

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 19 2016

STATUS

approved