login
Number of nonisomorphic unordered triples of derangements of an n-set.
2

%I #6 May 03 2023 21:36:55

%S 1,0,1,2,18,138,4642,211600,13511246,1092862024,109276859229,

%T 13221974420985,1903936637405380,321762396855180477,

%U 63065061524052355523,14189582409276961769144,3632522968870016652531332,1049797035002712952582167891,340133739324533632977813192678

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

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

%H Andrew Howroyd, <a href="/A362761/b362761.txt">Table of n, a(n) for n = 0..50</a>

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

%e {(123), (123), (123)},

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

%Y Column k=3 of A362759.

%Y Cf. A362646, A362760.

%K nonn

%O 0,4

%A _Andrew Howroyd_, May 02 2023