A189605 Number of nX4 array permutations with each element not moving, or moving one space E, S or NW.

1, 13, 72, 464, 2853, 17617, 108785, 671452, 4144996, 25586605, 157944449, 974979853, 6018479996, 37151644524, 229334423389, 1415664871777, 8738797243193, 53943965676260, 332992213004236, 2055536935944305

Offset: 1

Author

R. H. Hardin Apr 24 2011

Keywords

• nonn

Comments

Column 4 of A189610

Examples

			Some solutions for 3X4
..0..1..7..2....5..0..2..3....0..6..2..3....5..6..7..2....0..6..1..2
..4..5..6..3....4..1.11..6....9..1..5..7....0..1.11..3....9..5.11..3
..8..9.10.11....8..9.10..7....4..8.10.11....4..8..9.10....4..8.10..7
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 7*a(n-1) -3*a(n-2) -12*a(n-3) -11*a(n-4) +34*a(n-5) -27*a(n-6) +9*a(n-7) +7*a(n-8) +49*a(n-9) -82*a(n-10) +84*a(n-11) -54*a(n-12) +21*a(n-13) -6*a(n-14) +a(n-15)