login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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. 2

%I #4 May 27 2016 12:31:28

%S 4140,153063,3315645,55239525,786082275,10081916559,120278261103,

%T 1361959159275,14838761544750,157056039953670,1626124163724918,

%U 16555067600440590,166368479811851850,1655233308679110930,16341232769733507570,160366537782578273850

%N 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.

%H Alois P. Heinz, <a href="/A273658/b273658.txt">Table of n, a(n) for n = 8..1000</a>

%F E.g.f.: x^8/8! * Sum_{j=0..8} Stirling2(8,j)*exp(x)^j.

%F a(n) = C(n,8) * Sum_{j=0..8} Stirling2(8,j) * j^(n-8).

%p a:= n-> binomial(n,8)*add(Stirling2(8,j)*j^(n-8), j=0..8):

%p seq(a(n), n=8..40);

%Y Column k=8 of A143396.

%K nonn

%O 8,1

%A _Alois P. Heinz_, May 27 2016

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 23 06:04 EDT 2024. Contains 371906 sequences. (Running on oeis4.)