A268802 Number of n X n 0..2 arrays with some element plus some horizontally, vertically or antidiagonally adjacent neighbor totalling two not more than once.

3, 34, 332, 5848, 195384, 12432856, 1508087180, 348686105792, 154172619407288, 130573457756588328, 212323461305457440492, 663970589813116610557692, 3999438097971983178736358520, 46462227980008803491191644654968

Offset: 1

Author

R. H. Hardin, Feb 13 2016

Keywords

• nonn

Comments

Diagonal of A268809.

Examples

			Some solutions for n=4
..2..2..2..2. .0..0..1..2. .2..1..0..0. .0..1..0..0. .1..2..2..1
..1..1..2..2. .1..2..2..2. .2..0..0..0. .1..0..0..0. .2..2..2..2
..2..2..2..2. .2..2..1..2. .1..0..0..1. .0..0..0..1. .1..2..2..1
..1..2..1..2. .2..2..2..2. .0..0..0..0. .0..0..0..0. .2..1..2..1
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..18

Crossrefs

Cf. A268809.