A221133 Number of n X n arrays of occupancy after each element moves to some horizontal or vertical neighbor, with no occupancy greater than 2.

0, 9, 656, 643204, 4235650596, 259039174953636

Offset: 1

Author

R. H. Hardin Jan 02 2013

Keywords

• nonn

Comments

Diagonal of A221139

Examples

			Some solutions for n=3
..2..1..0....2..2..1....0..2..1....0..1..2....2..2..1....0..0..1....2..1..0
..1..2..1....2..0..1....2..1..0....1..0..2....1..0..2....1..1..2....2..2..1
..0..2..0....0..0..1....2..1..0....2..1..0....0..0..1....2..2..0....0..1..0