A215791 Number of permutations of 0..floor((5*n-1)/2) on even squares of an 5*n array such that each row, column, diagonal and (downwards) antidiagonal of even squares is increasing

1, 1, 1, 4, 25, 189, 2465, 26451, 530429, 7027942, 187205626, 2850280812

Offset

1,4

Comments

Row 5 of A215788

Links

Table of n, a(n) for n=1..12.

Example

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

Crossrefs

Sequence in context: A365764 A135147 A221382 * A175913 A239996 A064063

Adjacent sequences: A215788 A215789 A215790 * A215792 A215793 A215794

Keyword

nonn

Author

R. H. Hardin Aug 23 2012

Status

approved