A202026 Number of n X n zero-sum -1..1 arrays with rows and columns lexicographically nondecreasing

1, 7, 181, 29363, 29859761, 197324899476, 8770728360813539

Offset

1,2

Comments

Diagonal of A202033

Links

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

Example

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

Crossrefs

Sequence in context: A212944 A068339 A219404 * A302904 A059382 A158620

Adjacent sequences: A202023 A202024 A202025 * A202027 A202028 A202029

Keyword

nonn

Author

R. H. Hardin Dec 09 2011

Status

approved