A229165 a(n) is the number of n X n matrices of 0's, 1's and -1's in which the entries in each row or column sum to 1 and there are no adjacent -1's or 1's in any row or column.

1, 2, 7, 104, 7255, 2280064, 2708080414, 13039886441460

Offset: 1

Author

Eric W. Weisstein, Sep 25 2013

Keywords

• nonn
• more

Crossrefs

Cf. A005130 (Robbins numbers).

Cf. A050204 (entries in each row or column sum to 1).

Extensions

Additional terms from R. H. Hardin, Sep 25 2013