Let a(n) be the amount of natural numbers, which are smaller than n, and their prime divisors are only 2 and 3.
For example: 6 is good, because it only has 2 and 3 has prime divisors, but 10 is not good because it has 5 as a prime divisor. 12 is good too, because it's prime divisors are only 2 and 3, since 4 and 6 are not primes.
How much is a(n) asymptotic if n goes until infinity?