How many distinct (non-isomorphic) trees can be drawn for a graph of order n?

[futurebird]

Graph Theory Question:
I made this up after reading about trees

How many distinct (non-isomorphic) trees can be drawn for a graph of order n?

Comments

[laurent_atl]

i think that paper counts labeled trees, so there are 3 different trees with 3 vertices:

1-2-3, 2-3-1 and 2-1-3

and with 4 vertices:

1-2-3-4
1-2-4-3
1-3-2-4
1-3-4-2
1-4-2-3
1-4-3-2
2-1-3-4
2-1-4-3
3-1-2-4
3-1-4-2
4-1-3-2
4-1-2-3

and 4 others that are hard to draw in ascii...

[beezari]

Shouldn't we mention whether we are dealing with directional or bi-directional graph in this case? (my math isn't great though, so I may be messing up here:))

[futurebird]

Most of the time it is not a digraph unless they say so.