A224256 Number of n X n 0..2 arrays with rows, diagonals and antidiagonals unimodal and columns nondecreasing.

3, 36, 648, 12467, 238366, 4480391, 83124099, 1530419762, 28072690614, 514262753781, 9420094252771

Offset

1,1

Links

Table of n, a(n) for n=1..11.

Example

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

Crossrefs

Main diagonal of A224262.

Sequence in context: A305991 A203493 A296098 * A223912 A383315 A224184

Adjacent sequences: A224253 A224254 A224255 * A224257 A224258 A224259

Keyword

nonn,more

Author

R. H. Hardin, Apr 02 2013

Extensions

Name corrected by Andrew Howroyd, Mar 18 2025

Status

approved