A221407 Number of nX6 arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, with every occupancy equal to zero or two.

8, 328, 12668, 492102, 18852560, 722442370, 27665242848, 1058237377670

Offset: 1

Author

R. H. Hardin Jan 15 2013

Keywords

• nonn

Comments

Column 6 of A221408

Examples

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