A118991 Number of real n X n symmetric (0,1) matrices with nonzero permanent.

1, 5, 39, 753, 25887, 1842241, 247531775

Offset

1,2

Links

Table of n, a(n) for n=1..7.

Formula

a(n) = 2^(n(n+1)/2) - A118989(n) = 2^A000217(n) - A118989(n) = A006125(n+1) - A118989(n). [From Max Alekseyev, Apr 22 2010]

Crossrefs

Cf. A086899, A118989.

Sequence in context: A221412 A193118 A227636 * A253920 A156378 A220061

Adjacent sequences: A118988 A118989 A118990 * A118992 A118993 A118994

Keyword

nonn,more

Author

Giovanni Resta, May 08 2006

Extensions

Max Alekseyev's formula corrected (the term 2^(n^2), counting the total number of binary matrices, has been substituted for 2*2^2*...*2^n = 2^(n(n+1)/2), the total number of binary symmetric matrices) by Herman Jamke (hermanjamke(AT)fastmail.fm), Sep 26 2010

Status

approved