A202729 Number of n X n nonnegative integer arrays with each row and column an ascent sequence (interior element no greater than one plus up-steps preceding it) and the lower right element equal to n-1

1, 1, 2, 12, 304, 44976, 51871384, 600608922384, 87357442179208880, 194354337721367202187520

Offset

1,3

Comments

Diagonal of A202735

Links

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

Example

Some solutions for n=4
..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..0..1..1..1....0..0..1..1....0..0..0..1....0..1..1..1....0..0..1..1
..0..1..0..2....0..1..1..2....0..1..1..2....0..0..1..2....0..1..0..2
..0..1..2..3....0..1..2..3....0..1..2..3....0..1..2..3....0..1..2..3

Crossrefs

Sequence in context: A000178 A108395 A009669 * A012380 A012377 A012425

Adjacent sequences: A202726 A202727 A202728 * A202730 A202731 A202732

Keyword

nonn

Author

R. H. Hardin Dec 23 2011

Status

approved