Regex: only alphanumeric but not if this is pure numeric

Question

For instance:

\'1\'     => NG
\'243\'   => NG
\'1av\'   => OK
\'pRo\'   => OK
\'123k%\' => NG

I tried with

Answer 1

Try with this:

/^(?!^\d*$)[a-zA-Z\d]*$/

Edit: since this is essentially the same of the accepted answer, I'll give you something different:

/^\d*[a-zA-Z][a-zA-Z\d]*$/

No lookaheads, no repeated complex group, it just verifies that there's at least one alphabetic character. This should be quite fast.