A304946 Number of n X n 0..1 arrays with every element unequal to 0, 2, 3, 5 or 7 king-move adjacent elements, with upper left element zero.

1, 4, 13, 26, 189, 1916, 18950, 401301, 12197817, 468373258

Offset

1,2

Comments

Diagonal of A304952.

Links

Table of n, a(n) for n=1..10.

Example

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

Crossrefs

Cf. A304952.

Sequence in context: A206804 A304003 A305356 * A316616 A119652 A147875

Adjacent sequences: A304943 A304944 A304945 * A304947 A304948 A304949

Keyword

nonn

Author

R. H. Hardin, May 22 2018

Status

approved