A215793 Number of permutations of 0..floor((7*n-1)/2) on even squares of an 7*n array such that each row, column, diagonal and (downwards) antidiagonal of even squares is increasing

1, 1, 1, 8, 125, 2988, 146205, 6812794, 673507749, 48337803306

Offset

1,4

Comments

Row 7 of A215788

Links

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

Example

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

Crossrefs

Sequence in context: A215040 A033536 A355762 * A273279 A227851 A076960

Adjacent sequences: A215790 A215791 A215792 * A215794 A215795 A215796

Keyword

nonn

Author

R. H. Hardin Aug 23 2012

Status

approved