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A301902 Number of n X 3 0..1 arrays with every element equal to 0, 2 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero. 1
1, 2, 3, 7, 16, 43, 117, 330, 935, 2667, 7616, 21775, 62273, 178130, 509563, 1457727, 4170224, 11930147, 34129757, 97638522, 279324735, 799093699, 2286051744, 6539949991, 18709526921, 53524323778, 153122698291, 438054310967 (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) = 3*a(n-1) +a(n-2) -4*a(n-3).

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Column 3 of A301906.

Sequence in context: A162092 A143884 A227546 * A122031 A246829 A296231

Adjacent sequences:  A301899 A301900 A301901 * A301903 A301904 A301905

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 28 2018

STATUS

approved

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Last modified December 12 09:36 EST 2019. Contains 329953 sequences. (Running on oeis4.)