A222000 Number of n X n arrays with each row a permutation of 1..n having at least as many downsteps as the preceding row, with rows in lexicographically nonincreasing order.

1, 2, 22, 2470, 16011558, 3982479033010, 167454529339944721318, 448166024141727075228729619483

Offset

1,2

Comments

Diagonal of A222005

Links

Table of n, a(n) for n=1..8.

Example

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

Crossrefs

Sequence in context: A319620 A054349 A182293 * A261400 A113930 A181235

Adjacent sequences: A221997 A221998 A221999 * A222001 A222002 A222003

Keyword

nonn

Author

R. H. Hardin, Feb 03 2013

Status

approved