A118989 Number of symmetric n X n (0,1)-matrices over the reals with zero permanent.

1, 3, 25, 271, 6881, 254911, 20903681

Offset

1,2

Links

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

Formula

a(n) = 2^(n*(n+1)/2) - A118991(n) = 2^A000217(n) - A118991(n) = A006125(n+1) - A118991(n). [From Max Alekseyev, Apr 22 2010]

Crossrefs

Cf. A086906, A088672, A118991.

Sequence in context: A009042 A080896 A126746 * A229162 A363354 A347255

Adjacent sequences: A118986 A118987 A118988 * A118990 A118991 A118992

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