A221618 Number of n X n arrays with each row a permutation of 1..n having at least as many downsteps as the preceding row.

1, 3, 112, 85035, 3451956516, 7575106427737240, 2031241364747667201263520, 57096186419355436503540544000542003, 350680349722258761627197454626353435730368352560

Offset: 1

Author

R. H. Hardin Jan 21 2013

Keywords

• nonn

Comments

Diagonal of A221623

Examples

			Some solutions for n=3
..1..2..3....1..2..3....3..1..2....3..1..2....2..1..3....1..2..3....2..3..1
..2..1..3....3..1..2....3..1..2....2..3..1....1..3..2....1..3..2....3..1..2
..3..2..1....3..2..1....2..3..1....3..1..2....2..3..1....3..2..1....3..1..2
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..12