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A036980 Number of (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
FORMULA
a(n) = A035483(n) * (2n)!
CROSSREFS
Sequence in context: A064069 A065128 A122222 * A337653 A168442 A091810
KEYWORD
more,nonn
AUTHOR
Joshua Zucker and Joe Keane
STATUS
approved

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Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)