On the classification of integers by missing primes

On the classification of integers by missing primes

If p1,p2,p3,.. is the sequence of prime numbers then any positive integer can be written:

n=pi^a1*p2^a2*p3^a3...pq^aq

where q is a positive integer and ai are integers greater than or equal to zero.

Of course, if ai=0 then pi^ai=1 and we say that the prime pi is "missing" from n.

I wonder if it would be instructive to classify integers by their missing primes?
As a special case: if n is prime then it has the maximum possible number of missing primes.

Content written and posted by Ken Abbott abbottsystems@gmail.com