A280548 Number of n X n 0..1 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

0, 0, 50, 382, 1764, 6502, 20334, 56102, 141398, 332810, 743966, 1598198, 3328362, 6763114

Offset: 1

Author

R. H. Hardin, Jan 05 2017

Keywords

• nonn

Comments

Diagonal of A280554.

Examples

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

Crossrefs

Cf. A280554.