I agree with Earthborn, surprisingly good.

Especially considering its modest size. Well done.

Obvously, you could devote a lot of time trying to hardcode solutions to anticipated sequences such as the ones suggested, but...that would be cheating! It would be like sticking a guy inside a box and presenting it as a chess playing 'machine'. Not only that, but it might turn out to be almost as overwhelming an undertaking as writing a genuine AI program -- like I said before, there are a LOT of possibilities:
http://www.research.att.com/~njas/sequences/