A215296 Number of permutations of 0..floor((n*7-2)/2) on odd squares of an nX7 array such that each row and column of odd squares is increasing.

1, 35, 1050, 210210, 14294280, 5703417720, 577185873264, 337653735859440, 43364386933948080, 32436561426593163840, 4886336289191784467040, 4340695403565368534887200, 733267473530864041786302000

Offset: 1

Author

R. H. Hardin Aug 07 2012

Keywords

• nonn

Comments

Column 7 of A215297

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

f3=floor((n+1)/2)

f4=floor(n/2)

a(n) = A060854(3,f3)*A060854(4,f4)*binomial(3*f3+4*f4,3*f3)