A221690 Number of nX4 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, without consecutive moves in the same direction.

13, 1336, 95076, 7033429, 520770016, 38558774282, 2854945130275, 211383822013331, 15651127479431664, 1158829375610866111, 85801199678309146886, 6352829859620504245102, 470371595862197876296617

Offset: 1

Author

R. H. Hardin Jan 22 2013

Keywords

• nonn

Comments

Column 4 of A221693

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..78