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A301994 Number of nX3 0..1 arrays with every element equal to 1, 2 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero. 1
1, 2, 5, 15, 48, 155, 499, 1602, 5137, 16467, 52784, 169199, 542375, 1738618, 5573261, 17865479, 57269040, 183579891, 588478091, 1886407378, 6047009817, 19384109803, 62137109808, 199184819687, 638500768991, 2046758546378, 6561026627701 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A301999.

LINKS

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

FORMULA

Empirical: a(n) = 5*a(n-1) -7*a(n-2) +4*a(n-3)

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Cf. A301999.

Sequence in context: A149925 A149926 A321467 * A289589 A071739 A268407

Adjacent sequences:  A301991 A301992 A301993 * A301995 A301996 A301997

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 30 2018

STATUS

approved

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Last modified December 5 05:51 EST 2020. Contains 338944 sequences. (Running on oeis4.)