A215869 Number of permutations of 0..floor((n*9-2)/2) on odd squares of an nX9 array such that each row, column, diagonal and (downwards) antidiagonal of odd squares is increasing

1, 14, 290, 11694, 307874, 14296434, 386699176, 18255280444, 494952307400, 23397688110992, 634501639410480, 29997930933948284, 813501010455768664, 38461009542931961924, 1043008988814913191696, 49311812528326463481148

Offset

1,2

Comments

Column 9 of A215870

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

Crossrefs

Sequence in context: A233069 A181192 A227580 * A262740 A158475 A116165

Adjacent sequences: A215866 A215867 A215868 * A215870 A215871 A215872

Keyword

nonn

Author

R. H. Hardin Aug 25 2012

Status

approved