Powerful number

A powerful number is a natural number m such that for every prime divisor p of m p2 divisor of m. Equivalently, is a potent number the product of a square number and a cube number m = a2b3 with natural numbers a and b. Paul Erdős and George Szekeres studied such numbers, Solomon W. Golomb called them powerful.

List of potent numbers from 1 to 1000:

Sequence A001694 in On- Line Encyclopedia of Integer Sequences

The series of the reciprocals of all potent numbers can be calculated using the Riemann ζ - function display closed. ( Golomb, 1970)

Here, the apery constant, for which there is not an exact representation such as for straight arguments of the Riemann zeta function. Your numerical value amounts to.