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A303684 Number of nX2 0..1 arrays with every element unequal to 2, 3 or 4 king-move adjacent elements, with upper left element zero. 12
0, 3, 5, 18, 61, 209, 702, 2381, 8069, 27330, 92581, 313641, 1062502, 3599373, 12193421, 41307034, 139933701, 474046225, 1605902110, 5440232205, 18429595637, 62432996082, 211501059173, 716491292025, 2427220807318, 8222571457613 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 2 of A303690.

LINKS

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

FORMULA

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

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Cf. A303690.

Sequence in context: A123793 A196420 A199676 * A022489 A176749 A145774

Adjacent sequences:  A303681 A303682 A303683 * A303685 A303686 A303687

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 28 2018

STATUS

approved

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Last modified September 22 02:03 EDT 2021. Contains 347605 sequences. (Running on oeis4.)