A224006 Number of n X n 0..2 arrays with rows nondecreasing and antidiagonals unimodal.

1, 3, 36, 868, 28541, 1108969, 47735665, 2200064042, 106468976628, 5346274348879, 276427362685199, 14638913051219770, 790954334539356094, 43473056647367595435, 2424900281957535784114, 137007153893707984264455

Offset

0,2

Links

Table of n, a(n) for n=0..15.

Example

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

Crossrefs

Main diagonal of A224012.

Sequence in context: A377548 A227251 A326273 * A004824 A132912 A303866

Adjacent sequences: A224003 A224004 A224005 * A224007 A224008 A224009

Keyword

nonn,more

Author

R. H. Hardin, Mar 30 2013

Extensions

a(0)=1 prepended by Alois P. Heinz, Sep 18 2025

Status

approved