A305643 Number of nXn 0..1 arrays with every element unequal to 0, 1, 3, 4, 5 or 6 king-move adjacent elements, with upper left element zero.

1, 5, 13, 137, 5547, 355620, 283691091, 724085314967, 4577126359940051

Offset

1,2

Comments

Diagonal of A305649.

Links

Table of n, a(n) for n=1..9.

Example

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

Crossrefs

Cf. A305649.

Sequence in context: A004063 A005764 A358922 * A316919 A099974 A247820

Adjacent sequences: A305640 A305641 A305642 * A305644 A305645 A305646

Keyword

nonn

Author

R. H. Hardin, Jun 07 2018

Status

approved