A215871 Number of permutations of 0..floor((3*n-2)/2) on odd squares of an 3Xn array such that each row, column, diagonal and (downwards) antidiagonal of odd squares is increasing

1, 1, 1, 2, 4, 12, 29, 110, 290, 1274, 3532, 17136, 49100, 255816, 750325, 4124406, 12310294, 70549050, 213446666, 1264752060, 3868253164, 23555382240, 72686739116, 452806924752

Offset

1,4

Comments

Row 3 of A215870

Links

Table of n, a(n) for n=1..24.

Example

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

Crossrefs

Sequence in context: A148183 A148184 A148185 * A130135 A048618 A083554

Adjacent sequences: A215868 A215869 A215870 * A215872 A215873 A215874

Keyword

nonn

Author

R. H. Hardin Aug 25 2012

Status

approved