A056990 Number of nonsingular n X n (-1,1)-matrices.

1, 2, 8, 192, 22272, 11550720, 25629327360, 236229525504000, 8858686914082897920, 1331751782100764385607680

Offset

0,2

Links

Table of n, a(n) for n=0..9.

Eric Weisstein's World of Mathematics, Nonsingular Matrix.

Formula

a(n) = 2^(2*n-1) * A055165(n-1) for n>=1.

Crossrefs

Cf. A055165, A056989.

Sequence in context: A009505 A305737 A028368 * A234637 A234632 A070235

Adjacent sequences: A056987 A056988 A056989 * A056991 A056992 A056993

Keyword

nonn,nice

Author

Eric W. Weisstein

Extensions

a(5) from Winston C. Yang (winston(AT)cs.wisc.edu), Aug 26 2000

a(6)-a(8) computed from A055165 by David desJardins, Apr 22 2001

a(9) from Max Alekseyev, computed from A055165, Jan 15 2007

a(0)=1 prepended by Alois P. Heinz, May 29 2024

Status

approved