A303722 Number of nX3 0..1 arrays with every element unequal to 0, 1, 2 or 3 king-move adjacent elements, with upper left element zero.

4, 21, 23, 46, 77, 151, 294, 549, 1051, 2032, 3877, 7421, 14262, 27333, 52371, 100472, 192665, 369353, 708294, 1358233, 2604287, 4993776, 9575821, 18361581, 35208486, 67513133, 129457227, 248235688, 475996017, 912729185, 1750170310, 3355977073

Offset

1,1

Comments

Column 3 of A303727.

Links

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

Formula

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

Example

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

Crossrefs

Cf. A303727.

Sequence in context: A370979 A076943 A138228 * A305225 A272954 A133784

Adjacent sequences: A303719 A303720 A303721 * A303723 A303724 A303725

Keyword

nonn

Author

R. H. Hardin, Apr 29 2018

Status

approved