

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.


1



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(n1) + 3*a(n2)  2*a(n3)  6*a(n4)  4*a(n5)  a(n6).
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 A291238 A110034
Adjacent sequences: A269080 A269081 A269082 * A269084 A269085 A269086


KEYWORD

nonn


AUTHOR

R. H. Hardin, Feb 19 2016


STATUS

approved



