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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. 2
1, 3, 73, 12787, 13698241 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

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.

LINKS

Table of n, a(n) for n=0..4.

CROSSREFS

Cf. A145676.

Sequence in context: A119017 A307232 A002667 * A121981 A215961 A231780

Adjacent sequences:  A145672 A145673 A145674 * A145676 A145677 A145678

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Mar 26 2009

EXTENSIONS

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

STATUS

approved

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Last modified October 23 17:32 EDT 2019. Contains 328373 sequences. (Running on oeis4.)