The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
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!)
A305839 Number of unlabeled forests of rooted trees with 2n edges and n connected components, in which the outdegree of each node is <= 2 and the symmetric group acts on the components. 2

%I #7 Jun 11 2018 14:29:04

%S 1,1,3,6,15,32,77,172,405,930,2180,5070,11914,27929,65829,155202,

%T 367053,868990,2061723,4897502,11652547,27757960,66210042,158103242,

%U 377957299,904439542,2166408422,5193894809,12463003846,29929966312,71933014935,173009938416

%N Number of unlabeled forests of rooted trees with 2n edges and n connected components, in which the outdegree of each node is <= 2 and the symmetric group acts on the components.

%H Alois P. Heinz, <a href="/A305839/b305839.txt">Table of n, a(n) for n = 0..400</a>

%F a(n) = A088326(2n,n) = A088326(2n+k,n+k) for k >= 0.

%Y Cf. A088326.

%K nonn

%O 0,3

%A _Alois P. Heinz_, Jun 11 2018

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 May 28 21:13 EDT 2024. Contains 372920 sequences. (Running on oeis4.)