A145675 Number of n X n {0,-1,1}-matrices A such that permanent( |A| ) = | det A |, where |A| is obtained from A by taking the absolute value of each entry.

1, 3, 73, 12787, 13698241

Offset: 0

Author

N. J. A. Sloane, Mar 26 2009

Keywords

• nonn

Comments

Also the number of n X n sign-nonsingular matrices (see reference for definition).

References

• Brualdi, Richard A. and Shader, Bryan L., On sign-nonsingular matrices and the conversion of the permanent into the determinant, in Applied Geometry and Discrete Mathematics (The Victor Klee Festschrift), pp. 117-134, DIMACS Ser. Discrete Math. Theoret. Comput. Sci., 4, Amer. Math. Soc., Providence, RI, 1991.

Crossrefs

Cf. A145676.

Extensions

a(1)-a(4) computed by Eric W. Weisstein, Mar 26 2009