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A295046 Number of n X 3 0..1 arrays with each 1 horizontally or vertically adjacent to 0 or 2 1s. 1
5, 19, 72, 270, 1027, 3879, 14691, 55589, 210418, 796360, 3014159, 11408021, 43177713, 163420621, 618521718, 2341006856, 8860343731, 33535006265, 126924727467, 480390130557, 1818201106700, 6881605261574, 26045793772285 (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) = 3*a(n-1) + 4*a(n-2) - 3*a(n-3) - 2*a(n-4) - 6*a(n-5) + 3*a(n-6) - a(n-7) + a(n-9).

Empirical g.f.: x*(5 + 4*x - 5*x^2 - 7*x^3 - 4*x^4 + 2*x^5 - x^6 + x^7 + x^8) / (1 - 3*x - 4*x^2 + 3*x^3 + 2*x^4 + 6*x^5 - 3*x^6 + x^7 - x^9). - Colin Barker, Feb 22 2019

EXAMPLE

Some solutions for n=7:

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

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

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

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

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

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

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

CROSSREFS

Column 3 of A295051.

Sequence in context: A343799 A289925 A047155 * A034548 A255455 A255444

Adjacent sequences:  A295043 A295044 A295045 * A295047 A295048 A295049

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 13 2017

STATUS

approved

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Last modified December 7 20:38 EST 2021. Contains 349589 sequences. (Running on oeis4.)