A268734 Number of n X n binary arrays with some 1 horizontally or vertically adjacent to some other 1 exactly once.

0, 4, 80, 2876, 200204, 29134076, 9039552112, 6084192150856, 8965720251221240, 29122359898196696856, 209490003763160695865576, 3348908247850171650090422060, 119286836904111393911302107179212

Offset: 1

Author

R. H. Hardin, Feb 12 2016

Keywords

• nonn

Comments

Diagonal of A268740.

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..26

Crossrefs

Cf. A268740.