A304421 Number of nX2 0..1 arrays with every element unequal to 1, 2, 3, 4 or 5 king-move adjacent elements, with upper left element zero.

1, 7, 25, 98, 383, 1493, 5824, 22717, 88609, 345626, 1348139, 5258513, 20511208, 80005441, 312066973, 1217239658, 4747930775, 18519645245, 72237207376, 281766419413, 1099050170857, 4286924185562, 16721455908083, 65223240622649

Offset

1,2

Comments

Column 2 of A304427.

Links

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

Formula

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

Example

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

Crossrefs

Cf. A304427.

Sequence in context: A261722 A256370 A199116 * A138729 A035509 A332942

Adjacent sequences: A304418 A304419 A304420 * A304422 A304423 A304424

Keyword

nonn

Author

R. H. Hardin, May 12 2018

Status

approved