A317758 Number of nXn 0..1 arrays with every element unequal to 0, 1 or 2 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

1, 6, 16, 43, 109, 266, 639, 1529, 3674, 8909, 21853, 54252, 136213, 345373, 882828, 2271143, 5871373, 15234214, 39633091, 103306417, 269641062, 704462713, 1841692605, 4816973880, 12602801545

Offset

1,2

Comments

Diagonal of A317764.

Links

Table of n, a(n) for n=1..25.

Example

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

Crossrefs

Cf. A317764.

Sequence in context: A283330 A263325 A107614 * A010915 A352115 A260384

Adjacent sequences: A317755 A317756 A317757 * A317759 A317760 A317761

Keyword

nonn

Author

R. H. Hardin, Aug 06 2018

Status

approved