A201346 Number of n X n 0..1 arrays with rows and columns lexicographically nondecreasing and every element equal to at least one horizontal or vertical neighbor

0, 4, 18, 191, 4860, 310036, 53350918, 26097731070, 37211940860240, 157260419809121989

Offset

1,2

Comments

Diagonal of A201353

Links

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

Example

Some solutions for n=5
..0..0..0..0..1....0..0..0..1..1....0..0..0..1..1....0..0..0..0..1
..0..0..0..1..1....0..0..1..0..0....0..0..0..1..1....0..0..1..1..1
..0..1..1..0..0....0..0..1..0..0....0..0..1..1..1....0..1..0..1..1
..1..0..1..0..0....0..0..1..0..0....0..0..1..1..1....1..1..0..1..0
..1..0..1..1..1....0..0..1..0..0....0..1..1..0..0....1..1..0..1..0

Crossrefs

Sequence in context: A058924 A260970 A154731 * A174663 A356561 A197786

Adjacent sequences: A201343 A201344 A201345 * A201347 A201348 A201349

Keyword

nonn

Author

R. H. Hardin Nov 30 2011

Status

approved