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A036981 (2n+1) X (2n+1) symmetric matrices each of whose rows is a permutation of 1..(2n+1). 5
1, 6, 720, 31449600, 444733651353600, 10070314878246926155776000, 614972203951464612786852376432607232000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Number of different schedules for 2n+2 teams. - Andres Cardemil (andrescarde(AT)yahoo.com), Nov 28, 2001

LINKS

Table of n, a(n) for n=0..6.

Minjia Shi, Li Xu, Denis S. Krotov, The number of the non-full-rank Steiner triple systems, arXiv:1806.00009 [math.CO], 2018.

Index entries for sequences related to tournaments

FORMULA

a(n) = A000438(n+1) * (2*n+1)!

CROSSREFS

Cf. A000438, A000474, A035481, A036980, A064120, A065594.

Sequence in context: A169668 A168467 A080369 * A343434 A202080 A271528

Adjacent sequences:  A036978 A036979 A036980 * A036982 A036983 A036984

KEYWORD

nonn,more

AUTHOR

Joshua Zucker and Joe Keane

EXTENSIONS

Two more terms computed from A000438 by Max Alekseyev, Jun 17 2011

STATUS

approved

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Last modified December 4 09:10 EST 2021. Contains 349484 sequences. (Running on oeis4.)