0,2

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

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.

Cf. A145676.

Sequence in context: A020517 A119017 A002667 this_sequence A162601 A093183 A125520

Adjacent sequences: A145672 A145673 A145674 this_sequence A145676 A145677 A145678

nonn

N. J. A. Sloane (njas(AT)research.att.com), Mar 26 2009

a(1)-a(4) computed by E. W. Weisstein (eric(AT)weisstein.com), Mar 26, 2009