I've literally *JUST FINISHED* a semester making a Connect4 Board game in Java
Amongst other very small programs... no AI, though I thought of trying....
As I understand it, a search tree looks at all the moves available and looks for the most favourable outcome from all the results.
How many levels will it have? 42 I should think, unless there's some rule that you can't make 42 moves without winning, but I don't know of one (btw, don't be surprised if by the end of the development of this you make wild Hitchhiker's Guide to the Galaxy quotes
How many entries? If I had my calculator with me, and I knew anything about working out permutations, I could give you an answer. Unfortunatly I never covered permutations in maths... sorry.
I'll ask my java lecturer if you like, he might know,