A215873 Number of permutations of 0..floor((5*n-2)/2) on odd squares of an 5Xn array such that each row, column, diagonal and (downwards) antidiagonal of odd squares is increasing

1, 1, 1, 4, 20, 189, 1642, 26451, 307874, 7027942, 98057806, 2850280812, 44974137856

Offset

1,4

Comments

Row 5 of A215870

Links

Table of n, a(n) for n=1..13.

Example

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

Crossrefs

Sequence in context: A364344 A368455 A213144 * A066917 A280078 A032081

Adjacent sequences: A215870 A215871 A215872 * A215874 A215875 A215876

Keyword

nonn

Author

R. H. Hardin Aug 25 2012

Status

approved