A187855 Number of 7-step king-knight's tours (piece capable of both kinds of moves) on an n X n board summed over all starting positions.

0, 0, 35328, 1533064, 10353632, 33908456, 76860784, 140714528, 225295032, 330074144, 454720992, 599118736, 763244128, 947095136, 1150671760, 1373974000, 1617001856, 1879755328, 2162234416, 2464439120, 2786369440, 3128025376

Offset: 1

Author

R. H. Hardin Mar 14 2011

Keywords

• nonn

Comments

Row 7 of A187850

Examples

			Some solutions for 4X4
..2..0..0..0....0..5..2..0....0..0..6..0....0..0..1..3....0..0..1..2
..1..3..4..0....1..6..7..0....0..2..1..0....0..4..2..6....0..0..0..3
..0..5..6..0....0..3..4..0....4..5..0..7....0..7..0..5....0..6..4..0
..0..0..7..0....0..0..0..0....3..0..0..0....0..0..0..0....0..0..5..7
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..50

Formula

Empirical: a(n) = 9862808*n^2 - 82444808*n + 168212080 for n>11