A304911 Number of labeled hyperforests spanning n vertices without singleton edges.

1, 0, 1, 4, 32, 351, 5057, 90756, 1956971, 49366904, 1427680932, 46590895869, 1694163054597, 67938488277050, 2978980898086377, 141801848209013050, 7282651452378019772, 401410357608479625207, 23635996827115264290005

Offset

0,4

Links

Table of n, a(n) for n=0..18.

Formula

E.g.f.: exp(A030019(x) - x - 1) where A030019(x) is the e.g.f. of A030019.

Example

The a(3) = 4 hyperforests are {{1,2,3}}, {{1,3},{2,3}}, {{1,2},{2,3}}, {{1,2},{1,3}}.

Crossrefs

Cf. A006126, A030019, A035053, A048143, A054921, A134954, A134955, A134957, A144959, A293993, A293994, A304716, A304717, A304867.

Sequence in context: A231446 A137432 A177750 * A224993 A357407 A319220

Adjacent sequences: A304908 A304909 A304910 * A304912 A304913 A304914

Keyword

nonn

Author

Gus Wiseman, May 20 2018

Status

approved