A221506 Number of nX4 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, without consecutive moves in the same direction.

1, 446, 31663, 2691211, 219689604, 18054912942, 1481559445366, 121595969760961, 9979148121938539, 818972532183106546, 67211557641378928789, 5515926988608836197348

Offset: 1

Author

R. H. Hardin Jan 18 2013

Keywords

• nonn

Comments

Column 4 of A221507

Examples

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