A303890 Number of nX2 0..1 arrays with every element unequal to 1, 2, 3 or 4 king-move adjacent elements, with upper left element zero.

1, 7, 23, 86, 313, 1145, 4184, 15293, 55895, 204294, 746685, 2729101, 9974744, 36457249, 133249635, 487021534, 1780042209, 6505975697, 23779053976, 86911392597, 317657303391, 1161023421462, 4243489354069, 15509766267621

Offset

1,2

Comments

Column 2 of A303896.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +a(n-2) +4*a(n-3) +4*a(n-4)

Example

Some solutions for n=5
..0..1. .0..1. .0..1. .0..1. .0..0. .0..1. .0..0. .0..0. .0..1. .0..1
..0..0. .1..0. .1..0. .1..1. .1..0. .0..1. .0..1. .1..0. .0..1. .0..1
..1..0. .1..1. .1..0. .0..1. .0..1. .0..0. .0..1. .0..1. .1..0. .1..1
..1..0. .1..1. .0..0. .0..1. .1..1. .1..1. .0..0. .0..0. .1..0. .0..0
..1..1. .0..1. .1..1. .0..0. .0..0. .0..0. .0..1. .1..0. .1..1. .0..1

Crossrefs

Cf. A303896.

Sequence in context: A093069 A341665 A322269 * A003540 A063793 A217233

Adjacent sequences: A303887 A303888 A303889 * A303891 A303892 A303893

Keyword

nonn

Author

R. H. Hardin, May 02 2018

Status

approved