A189444 Number of n X 4 array permutations with each element moving zero or one space horizontally or diagonally.

5, 61, 666, 7300, 80282, 883049, 9712873, 106834338, 1175098084, 12925203122, 142167601085, 1563737653381, 17199948722346, 189186616701220, 2080911781577162, 22888478678939969, 251756206521753553

Offset: 1

Author

R. H. Hardin, Apr 22 2011

Keywords

• nonn

Comments

Column 4 of A189449.

Examples

			Some solutions for 3 X 4:
..0..1..3..2....1..0..2..3....5..1..2..3....5..1..3..2....0..6..2..3
..4..5..7..6....9.10.11..7....9..0..7..6....4..0..7..6....9..4..1..7
..9..8.11.10....8..4..5..6....8..4.11.10....8..9.11.10....8.10..5.11
		

Links

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

Crossrefs

Cf. A189449.

Formula

Empirical: a(n) = 12*a(n-1) -12*a(n-2) +12*a(n-3) -12*a(n-4) +a(n-5).

Empirical g.f.: x*(5 + x - 6*x^2 - 20*x^3 + 2*x^4) / ((1 - x)*(1 - 11*x + x^2 - 11*x^3 + x^4)). - Colin Barker, May 02 2018