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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
OFFSET
0,4
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}}.
KEYWORD
nonn
AUTHOR
Gus Wiseman, May 20 2018
STATUS
approved