Is the distribution of "almost-primes" known.

tpm

If we define the "Almost-primes" as:

* [tex] p^{a} [/tex] a is positive integer and p is a prime

* pq where p and q are both primes

then my question is if their distribution known ?? i mean if there is a function f(x) so for f(N) gives the values of "almost prime numbers" from 1 to N

matt grime

Yes. But yo don't want to ask that. You want to ask if there is a way to express this function in terms of easily computed objects/quantities, or if there is a closed expression in n. Can't help you there.