Regex: match only letters WITH numbers

Question

How can I create a regex expression that will match only letters with numbers?

I\'ve tried something like (?>[A-z]+)([a-z0-9]+).

Answer 1

^([a-Z]+[0-9]+|[0-9]+[a-Z]+)[a-Z0-9]*$

and a simpler version inspired by TimPietzcker:

^([a-Z]+[0-9]|[0-9]+[a-Z])[a-Z0-9]*$