A215787 Number of permutations of 0..floor((n*9-1)/2) on even squares of an nX9 array such that each row, column, diagonal and (downwards) antidiagonal of even squares is increasing

1, 14, 462, 11694, 530429, 14296434, 673507749, 18255280444, 862827082115, 23397688110992, 1106178923600669, 29997930933948284, 1418251919293188195, 38461009542931961924, 1818375422885354065137, 49311812528326463481148

Offset

1,2

Comments

Column 9 of A215788

Links

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

Formula

Empirical: a(n) = 1385*a(n-2) -131648*a(n-4) -318070*a(n-6) -4160916*a(n-8) -1097892*a(n-10) +648*a(n-12)

Example

Some solutions for n=4
..0..x..1..x..3..x..6..x..8....0..x..1..x..2..x..6..x.11
..x..2..x..5..x.10..x.13..x....x..3..x..5..x..8..x.12..x
..4..x..7..x.11..x.14..x.15....4..x..7..x.10..x.14..x.16
..x..9..x.12..x.16..x.17..x....x..9..x.13..x.15..x.17..x

Crossrefs

Sequence in context: A282245 A319096 A297548 * A005790 A208563 A200061

Adjacent sequences: A215784 A215785 A215786 * A215788 A215789 A215790

Keyword

nonn

Author

R. H. Hardin Aug 23 2012

Status

approved