[Dylan16807]

I don't think you want a factorial involved.

With unknown size, cracking 30 characters takes time proportional to n^30 + n^29 + n^28 etc.

Cracking just 30 is proportional to n^30.

The difference is negligible. A percent or two.

[luis8]

My bad, I was thinking in permutations but those does not allow repeated entries. It make sense now, like you said the difference is negligible.