A358648 Number of preference profiles of the stable roommates problem with 2n participants.

1, 1296, 2985984000000, 416336312719673760153600000000, 39594086612242519324387557078266845776303882240000000000, 16363214235219603423192858350259453436046713251360764276842772299776000000000000000000000000

Offset: 1

Author

Dan Eilers, Nov 24 2022

Keywords

• nonn
• easy

Comments

Each participant ranks all participants other than themselves in strict order, giving (2n-1)! orderings for each of 2n participants.

Links

• Wikipedia, Stable Roommates Problem

Crossrefs

Cf. A356584 (up to isomorphism), A185141 (Stable Marriage profiles), A001147 (possible roommate pairings).

Even bisection of A091868.

Programs

Mathematica

Table[(2n-1)!^(2n), {n, 1, 6}]

Formula

a(n) = (2n-1)!^(2n).