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A269084 Number of n X 3 binary arrays with some element plus some horizontally, vertically or antidiagonally adjacent neighbor totalling two not more than once. 1
7, 30, 114, 428, 1531, 5387, 18590, 63347, 213490, 713237, 2365217, 7794642, 25549763, 83359179, 270860625, 876943006, 2830104798, 9107202178, 29230933367, 93601324315, 299085155918, 953808773503, 3036347307176, 9649992762591 (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) = 2*a(n-1) + 9*a(n-2) - 2*a(n-3) - 33*a(n-4) - 42*a(n-5) - 14*a(n-6) + 10*a(n-7) + 8*a(n-8) - a(n-10).

Empirical g.f.: x*(7 + 16*x - 9*x^2 - 56*x^3 - 60*x^4 - 15*x^5 + 13*x^6 + 8*x^7 - x^8 - x^9) / ((1 + x)^2*(1 - 2*x - 3*x^2 - x^3 + x^4)^2). - Colin Barker, Jan 19 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 3 of A269089.

Sequence in context: A276289 A062455 A085277 * A055269 A026631 A037709

Adjacent sequences:  A269081 A269082 A269083 * A269085 A269086 A269087

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 19 2016

STATUS

approved

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Last modified May 21 17:17 EDT 2019. Contains 323444 sequences. (Running on oeis4.)