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A358648
Number of preference profiles of the stable roommates problem with 2n participants.
0
1, 1296, 2985984000000, 416336312719673760153600000000, 39594086612242519324387557078266845776303882240000000000, 16363214235219603423192858350259453436046713251360764276842772299776000000000000000000000000
OFFSET
1,2
COMMENTS
Each participant ranks all participants other than themselves in strict order, giving (2n-1)! orderings for each of 2n participants.
FORMULA
a(n) = (2n-1)!^(2n).
MATHEMATICA
Table[(2n-1)!^(2n), {n, 1, 6}]
CROSSREFS
Cf. A356584 (up to isomorphism), A185141 (Stable Marriage profiles), A001147 (possible roommate pairings).
Even bisection of A091868.
Sequence in context: A067492 A222338 A013841 * A256834 A031750 A345956
KEYWORD
nonn,easy
AUTHOR
Dan Eilers, Nov 24 2022
STATUS
approved