A036980 Number of (2n) X (2n) symmetric matrices each of whose rows is a permutation of 1..(2n).

1, 2, 96, 328320, 440952422400

Offset

0,2

Links

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

Formula

a(n) = A035483(n) * (2n)!

Crossrefs

Cf. A035481, A036981.

Sequence in context: A064069 A065128 A122222 * A337653 A168442 A091810

Adjacent sequences: A036977 A036978 A036979 * A036981 A036982 A036983

Keyword

more,nonn

Author

Joshua Zucker and Joe Keane

Status

approved