a(n) is the number of labeled rooted trees on a set of size n where each node has at most 4 neighbors that are further away from the root than the node itself.

A036776

a(n) is the number of labeled rooted trees on a set of size n where each node has at most 4 neighbors that are further away from the root than the node itself.

Terms

    a(0) =0a(1) =1a(2) =2a(3) =9a(4) =64a(5) =625a(6) =7770a(7) =117390a(8) =2088520a(9) =42771960a(10) =991090800a(11) =25635767850a(12) =732235165200

External references