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.

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

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