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A036980 (2n)x(2n) symmetric matrices each of whose rows is a permutation of 1..(2n). 2
1, 2, 96, 328320, 440952422400 (list; graph; refs; listen; history; text; internal format)
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 * A168442 A091810 A165642

Adjacent sequences:  A036977 A036978 A036979 * A036981 A036982 A036983

KEYWORD

more,nonn

AUTHOR

Joshua Zucker and Joe Keane

STATUS

approved

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Last modified March 25 10:16 EDT 2019. Contains 321470 sequences. (Running on oeis4.)