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A301836 Number of nX3 0..1 arrays with every element equal to 0, 1 or 2 horizontally or antidiagonally adjacent elements, with upper left element zero. 1
4, 25, 139, 773, 4299, 23909, 132971, 739525, 4112907, 22874149, 127215787, 707517317, 3934894923, 21884125925, 121709722091, 676895047237, 3764587553931, 20936952499621, 116441967065899, 647598149464325 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A301841.

LINKS

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

FORMULA

Empirical: a(n) = 7*a(n-1) -8*a(n-2) for n>3

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Cf. A301841.

Sequence in context: A015533 A207410 A278275 * A275177 A079291 A173612

Adjacent sequences:  A301833 A301834 A301835 * A301837 A301838 A301839

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 27 2018

STATUS

approved

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Last modified September 26 02:28 EDT 2020. Contains 337346 sequences. (Running on oeis4.)