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A305225 Number of nX3 0..1 arrays with every element unequal to 0, 1, 2, 3 or 8 king-move adjacent elements, with upper left element zero. 1
4, 21, 24, 54, 108, 236, 509, 1091, 2363, 5109, 11034, 23867, 51606, 111571, 241263, 521680, 1128006, 2439107, 5274072, 11404090, 24659080, 53320283, 115294335, 249300825, 539062799, 1165614674, 2520407019, 5449872468, 11784251403 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A305230.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) +a(n-2) -3*a(n-4) -a(n-5) +2*a(n-6) for n>9

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Cf. A305230.

Sequence in context: A076943 A138228 A303722 * A272954 A133784 A041821

Adjacent sequences:  A305222 A305223 A305224 * A305226 A305227 A305228

KEYWORD

nonn

AUTHOR

R. H. Hardin, May 27 2018

STATUS

approved

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Last modified September 27 07:30 EDT 2022. Contains 357052 sequences. (Running on oeis4.)