A281198 Number of n X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

0, 2, 56, 270, 1141, 4248, 14375, 45614, 138676, 409976, 1190740, 3421202, 9767347, 27782656, 78849645

Offset: 1

Author

R. H. Hardin, Jan 17 2017

Keywords

• nonn

Comments

Diagonal of A281205.

Examples

			Some solutions for n=4
..0..1..0..1. .0..1..0..1. .0..0..1..1. .0..1..1..0. .0..1..0..1
..0..0..1..0. .1..1..0..0. .1..0..1..0. .0..0..1..0. .0..1..0..0
..1..0..1..0. .0..1..1..0. .1..0..1..0. .1..0..1..1. .0..1..0..1
..1..0..1..1. .0..0..1..0. .1..0..1..0. .0..1..0..0. .0..1..0..0
		

Crossrefs

Cf. A281205.