A185827 Half the number of n X n binary arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

0, 3, 30, 514, 15782, 923808, 91052720, 17200095426, 5976334149476, 3829861209246738

Offset: 1

Author

R. H. Hardin Feb 05 2011

Keywords

• nonn

Comments

Diagonal of A185835

Examples

			Some solutions for 4X4 with a(1,1)=0
..0..0..1..1....0..0..1..1....0..0..0..1....0..1..1..1....0..0..1..1
..1..1..0..1....0..1..0..1....1..1..0..1....0..1..0..0....0..1..0..0
..0..0..0..1....0..1..0..1....0..1..0..1....0..1..1..0....1..1..0..1
..0..1..1..1....0..1..0..0....0..0..1..1....0..0..1..0....0..0..1..1