Oh I really just forgot the "in all other cases" part... :D Actually I never print the number, only in the loop but that was just to check the result.
But I have to say that it is hard to write "good" code without a real use case. In my opinion a one-liner (like @benniebanana suggested) is often a perfect copy/paste solution for simple and unshakable logic. I like code that is confident enough to say "Don't f***ing touch me. I just work! Please do the same!"
Concerning the if-statements I find my version more readable but that's maybe only because I am so used to do it that way. But I don't see any problems with that anyway. Also the function could return null.... maybe that's an issue. But we're in the PHP world here... :P It's like asking your 8 yo child to look after your 4 yo one while you're at work. You get prettily painted walls but the cake doesn't taste that well. :D
Anyway... your competition could become very funny and educational. Keep it on!