A240650 Number of n X n 0..1 arrays with no element equal to exactly one horizontal or vertical neighbor, with new values 0..1 introduced in row major order.

1, 2, 9, 91, 2456, 184819, 37066859, 18940533171, 24272278810439, 77660940030730106

Offset: 1

Author

R. H. Hardin, Apr 09 2014

Keywords

• nonn

Comments

Diagonal of A240656

Examples

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