A221854 Number of 3Xn arrays of occupancy after each element stays put or moves to some horizontal, diagonal or antidiagonal neighbor, without consecutive moves in the same direction.

1, 306, 10085, 465305, 19159028, 811781250, 34109464173, 1436352539452, 60446151885851, 2544184795092968

Offset: 1

Author

R. H. Hardin Jan 27 2013

Keywords

• nonn

Comments

Row 3 of A221852

Examples

			Some solutions for n=3
..2..1..1....0..1..0....0..0..1....2..1..0....1..1..3....1..0..0....1..0..2
..0..0..0....0..3..2....0..4..1....1..0..1....0..0..1....1..3..1....3..0..1
..3..1..1....0..3..0....0..1..2....1..3..0....0..2..1....2..1..0....0..2..0