A304691 Number of n X n 0..1 arrays with every element unequal to 1, 2, 3, 5 or 6 king-move adjacent elements, with upper left element zero.

0, 7, 56, 918, 37050, 2753404, 389403912, 111681916203, 65358224695742

Offset

1,2

Comments

Diagonal of A304697.

Links

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

Example

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

Crossrefs

Cf. A304697.

Sequence in context: A099345 A245249 A110830 * A218428 A365102 A274721

Adjacent sequences: A304688 A304689 A304690 * A304692 A304693 A304694

Keyword

nonn

Author

R. H. Hardin, May 17 2018

Status

approved