Forgive me if this is a stupid question, but I've been a long time away from regular expressions. If you wanted to check a username and make sure it was all alphanumeric, but didn't start with a number, would the following be right?

/^[a-z]+[a-z\d_]{3,27}$/iD



Edit: er, maybe this would make more sense?
/^[a-z]{1}[a-z\d_]{3,27}$/iD