A201532 Number of n X n 0..2 arrays with rows and columns lexicographically nondecreasing and every element equal to at least one horizontal or vertical neighbor

0, 9, 111, 7799, 2446147, 3762507339, 28456420346436

Offset

1,2

Comments

Diagonal of A201539

Links

Table of n, a(n) for n=1..7.

Example

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

Crossrefs

Sequence in context: A082723 A352384 A143167 * A180788 A348068 A241804

Adjacent sequences: A201529 A201530 A201531 * A201533 A201534 A201535

Keyword

nonn

Author

R. H. Hardin Dec 02 2011

Status

approved