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A269013 Number of 3 X n binary arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two exactly once. 1
0, 15, 46, 305, 1078, 4948, 18210, 73277, 270458, 1026795, 3757996, 13847240, 50155940, 181596651, 651546278, 2331910405, 8300115170, 29460799452, 104176325510, 367430075801, 1292287850546, 4534933300095, 15878737307224 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) + 8*a(n-2) - 34*a(n-3) - 16*a(n-4) + 60*a(n-5) - 25*a(n-6).

Empirical g.f.: x^2*(15 - 14*x + x^2) / (1 - 2*x - 6*x^2 + 5*x^3)^2. - Colin Barker, Jan 18 2019

EXAMPLE

Some solutions for n=4:

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

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

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

CROSSREFS

Row 3 of A269011.

Sequence in context: A041436 A219885 A042007 * A041438 A045111 A031451

Adjacent sequences:  A269010 A269011 A269012 * A269014 A269015 A269016

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 17 2016

STATUS

approved

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Last modified October 24 01:33 EDT 2021. Contains 348217 sequences. (Running on oeis4.)