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A317890 Number of nX2 0..1 arrays with every element unequal to 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. 3
0, 1, 1, 2, 5, 16, 45, 123, 340, 946, 2629, 7298, 20260, 56254, 156197, 433691, 1204165, 3343437, 9283266, 25775569, 71567464, 198711505, 551734847, 1531926100, 4253488018, 11810073809, 32791403882, 91047370756, 252798683166 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Column 2 of A317896.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) +a(n-2) +2*a(n-3) +3*a(n-4) +a(n-5) for n>6

EXAMPLE

All solutions for n=5

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

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

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

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

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

CROSSREFS

Cf. A317896.

Sequence in context: A148374 A182884 A152428 * A138573 A148375 A075887

Adjacent sequences:  A317887 A317888 A317889 * A317891 A317892 A317893

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 10 2018

STATUS

approved

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Last modified July 5 15:05 EDT 2022. Contains 355099 sequences. (Running on oeis4.)