Does anyone have a formula for the density of squarefree numbers as a function of the number of primes they contain?

The same for Squarefull would also be nice?

Squarefree -- From MathWorld (http://mathworld.wolfram.com/Squarefree.html) is a site that might be able to help you.

Thanks RosieJ but I use the Mathworld site on a regular basis.