P154: Enumeration of all rooted trees with at most $n$ vertices

P154: Enumeration of all rooted trees with at most $n$ vertices

Input:

An integer $n$.

Output:

All rooted tree with at most $n$ vertices.

Complexity:

$O(1)$ time per tree and $O(n)$ space.

Comment:

Reference:

[Nakano2003] (Bibtex)