A273658 Number of forests of labeled rooted trees of height at most 1, with n labels, eight of which are used for root nodes and any root may contain >= 1 labels.
4140, 153063, 3315645, 55239525, 786082275, 10081916559, 120278261103, 1361959159275, 14838761544750, 157056039953670, 1626124163724918, 16555067600440590, 166368479811851850, 1655233308679110930, 16341232769733507570, 160366537782578273850
Offset: 8
Keywords
Links
- Alois P. Heinz, Table of n, a(n) for n = 8..1000
Crossrefs
Column k=8 of A143396.
Programs
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Maple
a:= n-> binomial(n,8)*add(Stirling2(8,j)*j^(n-8), j=0..8): seq(a(n), n=8..40);
Formula
E.g.f.: x^8/8! * Sum_{j=0..8} Stirling2(8,j)*exp(x)^j.
a(n) = C(n,8) * Sum_{j=0..8} Stirling2(8,j) * j^(n-8).