A118996 Number of real n X n symmetric (0,1) matrices with negative determinant.

0, 3, 27, 190, 4410, 753592, 127793708, 21893984392, 9100020369720, 16451259308386616

Offset

1,2

Links

Table of n, a(n) for n=1..10.

Formula

a(n) = A086899(n) - A086900(n) = 2^(n*(n+1)/2) - A086906(n) - A086900(n). - Max Alekseyev, Jun 12 2025

Crossrefs

Cf. A086899, A086900, A086906, A118997, A118998, A118999, A119006.

Sequence in context: A251732 A385034 A145241 * A267947 A230170 A043023

Adjacent sequences: A118993 A118994 A118995 * A118997 A118998 A118999

Keyword

nonn,more

Author

Giovanni Resta, May 08 2006

Extensions

a(8)-a(10) from Max Alekseyev, Jun 17 2025

Status

approved