TextPad regular expression negation with a min/max

Question

In TextPad I am trying to find any line that does not start with a 6 or 7 digit number. So it should find all lines that do not look like:

"123456" or "1234567"

I wrote this expression:

^[^(\d{6,7})]

It is not finding lines that start with only 2 digits like this:

"12 months"

Maybe because the min/max {} expression isn't applying to the negate statement?

Thanks