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A304911 Number of labeled hyperforests spanning n vertices without singleton edges. 17
1, 0, 1, 4, 32, 351, 5057, 90756, 1956971, 49366904, 1427680932, 46590895869, 1694163054597, 67938488277050, 2978980898086377, 141801848209013050, 7282651452378019772, 401410357608479625207, 23635996827115264290005 (list; graph; refs; listen; history; text; internal format)
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 A319220 A051489

Adjacent sequences:  A304908 A304909 A304910 * A304912 A304913 A304914

KEYWORD

nonn

AUTHOR

Gus Wiseman, May 20 2018

STATUS

approved

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Last modified May 7 20:35 EDT 2021. Contains 343652 sequences. (Running on oeis4.)