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

A202026

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

Terms

    a(0) =1a(1) =7a(2) =181a(3) =29363a(4) =29859761a(5) =197324899476

External references