A201489 Number of n X n zero-sum -2..2 arrays with rows and columns lexicographically nondecreasing.

1, 29, 9331, 50432052, 4585552158911, 7383126698273869479

Offset: 1

Author

R. H. Hardin Dec 02 2011

Keywords

• nonn

Comments

Diagonal of A201496

Examples

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