A268632 Number of n X n 0..2 arrays with some element plus some horizontally or vertically adjacent neighbor totalling two exactly once.

0, 24, 840, 47640, 5419992, 1328460312, 725187096504, 897937832100888, 2550310193527246056, 16737195174968513278656, 255111495114527014241534160, 9064348272085612349020943764248, 752834148761621410865592159869765856

Offset: 1

Author

R. H. Hardin, Feb 09 2016

Keywords

• nonn

Comments

Diagonal of A268639.

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..14

Crossrefs

Cf. A268639.