The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.



(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A304067 Number of trees with n vertices rooted at a non-edge. 2


%S 0,0,1,3,9,27,79,233,679,1987,5784,16864,49063,142821,415439,1208761,

%T 3516475,10232428,29778138,86682119,252382445,735040515,2141319946,

%U 6239913801,18188637903,53033228465,154674931182,451247206423

%N Number of trees with n vertices rooted at a non-edge.

%F a(n) + A027852(n) = A303833(n).

%e a(3)=1: the non-edge joins two leaves. a(4)=3: The non-edge joins two leaves of the star graph; or the non-edge joins the two leaves of the linear graph; or the non-edge joins a leaf with the node at distance 2.

%Y Cf. A000055 (not rooted), A027852 (rooted at an edge), A304068 (rooted at an oriented non-edge).

%K nonn

%O 1,4

%A _Brendan McKay_, May 05 2018

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 20 01:20 EDT 2021. Contains 343117 sequences. (Running on oeis4.)