A186831 Number of (n+2)X(n+2) binary arrays with 3X3 subblock sums nondecreasing rightwards and downwards.

512, 19904, 1537476, 209888936, 21242244160, 3176962520030

Offset

1,1

Comments

Diagonal of A186840

Links

Table of n, a(n) for n=1..6.

Example

Some solutions for 4X4
..1..0..1..0....1..0..1..0....1..1..0..0....0..0..0..0....1..1..0..1
..1..0..0..1....0..0..1..1....0..0..1..1....0..0..0..1....0..0..0..1
..0..0..0..1....1..1..1..1....0..1..1..0....1..0..0..0....1..1..0..0
..1..1..0..1....1..1..0..1....1..1..0..0....1..1..1..1....0..1..1..0

Crossrefs

Sequence in context: A231308 A254735 A254914 * A236215 A254182 A253954

Adjacent sequences: A186828 A186829 A186830 * A186832 A186833 A186834

Keyword

nonn

Author

R. H. Hardin, Feb 27 2011

Status

approved