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

1,3

Comments

Row 7 of A187850

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

Example

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

Crossrefs

Sequence in context: A254016 A254023 A254890 * A300762 A250978 A282129

Adjacent sequences: A187852 A187853 A187854 * A187856 A187857 A187858

Keyword

nonn

Author

R. H. Hardin Mar 14 2011

Status

approved