A215786 Number of permutations of 0..floor((n*8-1)/2) on even squares of an nX8 array such that each row, column, diagonal and (downwards) antidiagonal of even squares is increasing

1, 5, 110, 932, 26451, 234217, 6812794, 60485308, 1761748159, 15643423061, 455678075546, 4046220880948, 117863060852067, 1046572601513969, 30485799411892266, 270700616010831020, 7885286478349158743

Offset

1,2

Comments

Column 8 of A215788

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 272*a(n-2) -3439*a(n-4) -3336*a(n-6) +140*a(n-8)

Example

Some solutions for n=4
..0..x..1..x..3..x..7..x....0..x..1..x..2..x..3..x....0..x..1..x..2..x..5..x
..x..2..x..4..x..9..x.10....x..4..x..6..x..7..x..8....x..3..x..4..x..7..x.11
..5..x..6..x.11..x.12..x....5..x..9..x.10..x.12..x....6..x..8..x..9..x.13..x
..x..8..x.13..x.14..x.15....x.11..x.13..x.14..x.15....x.10..x.12..x.14..x.15

Crossrefs

Sequence in context: A177680 A281762 A265082 * A053133 A203367 A322631

Adjacent sequences: A215783 A215784 A215785 * A215787 A215788 A215789

Keyword

nonn

Author

R. H. Hardin Aug 23 2012

Status

approved