A273655 Number of forests of labeled rooted trees of height at most 1, with n labels, five of which are used for root nodes and any root may contain >= 1 labels.
52, 906, 9891, 87416, 686826, 5020092, 35006202, 236460312, 1562226237, 10158790642, 65294141913, 415967090448, 2631510433188, 16551428673528, 103578621308388, 645186720537744, 4000912828433199, 24700465510596414, 151810205132056779, 928768921758036744
Offset: 5
Keywords
Links
- Alois P. Heinz, Table of n, a(n) for n = 5..1000
Crossrefs
Column k=5 of A143396.
Programs
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Maple
a:= n-> binomial(n,5)*add(Stirling2(5,j)*j^(n-5), j=0..5): seq(a(n), n=5..40);
Formula
E.g.f.: x^5/5! * Sum_{j=0..5} Stirling2(5,j)*exp(x)^j.
a(n) = C(n,5) * Sum_{j=0..5} Stirling2(5,j) * j^(n-5).