A362761 - OEIS

A362761

Number of nonisomorphic unordered triples of derangements of an n-set.

1, 0, 1, 2, 18, 138, 4642, 211600, 13511246, 1092862024, 109276859229, 13221974420985, 1903936637405380, 321762396855180477, 63065061524052355523, 14189582409276961769144, 3632522968870016652531332, 1049797035002712952582167891, 340133739324533632977813192678

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OFFSET

0,4

COMMENTS

Isomorphism is up to permutation of the elements of the n-set.

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..50

EXAMPLE

The a(3) = 2 nonisomorphic triples of derangements are:

{(123), (123), (123)},

{(123), (123), (132)}.

CROSSREFS