A215875 Number of permutations of 0..floor((7*n-2)/2) on odd squares of an 7Xn array such that each row, column, diagonal and (downwards) antidiagonal of odd squares is increasing

1, 1, 1, 8, 100, 2988, 97289, 6812794, 386699176, 48337803306

Offset

1,4

Comments

Row 7 of A215870

Links

Table of n, a(n) for n=1..10.

Example

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

Crossrefs

Sequence in context: A274844 A302944 A060570 * A317598 A238947 A291536

Adjacent sequences: A215872 A215873 A215874 * A215876 A215877 A215878

Keyword

nonn

Author

R. H. Hardin Aug 25 2012

Status

approved