A186906 Number of (n+2)X(n+2) 0..6 arrays with each 3X3 subblock having rows and columns in lexicographically nondecreasing order.

2066505, 2974946682, 4813465754996, 8185872059408158, 14077041692560748494, 23991605690718487651365, 40128119810449322920431346, 65662514004587268399842833783

Offset: 1

Author

R. H. Hardin Feb 28 2011

Keywords

• nonn

Comments

Diagonal of A186915

Examples

			Some solutions for 4X4
..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..1..1..1..4....0..0..3..5....0..0..3..6....0..1..2..4....0..1..1..3
..3..4..6..6....5..6..0..6....1..5..3..6....4..6..1..0....0..1..4..1