A118995 Number of real n X n symmetric (+1,-1) matrices with positive permanent.

1, 4, 32, 592, 11904, 1192384, 134217728, 41896879104, 16885168208896

Offset: 1

Author

Giovanni Resta, May 08 2006

Keywords

• nonn
• more

Crossrefs

Cf. A086900, A118988, A118999, A118993, A118994, A118999, A119001, A119010.

Formula

a(n) = A118993(n) - A118999(n). For odd n, a(n) = A118999(n) = A118993(n)/2. - Max Alekseyev, Jun 18 2025

Extensions

a(8)-a(9) from Max Alekseyev, Jun 18 2025