Square-free Integer - Squarefree Core

Squarefree Core

The multiplicative function is defined to map positive integers n to t-free numbers by reducing the exponents in the prime power representation modulo t:

The value set of, in particular, are the square-free integers. Their Dirichlet generating functions are

\sum_{n\ge 1}\frac{\mathrm{core}_t(n)}{n^s}
= \frac{\zeta(ts)\zeta(s-1)}{\zeta(ts-t)}.

OEIS representatives are  A007913 (t=2),  A050985 (t=3) and  A053165 (t=4).

Read more about this topic:  Square-free Integer

Famous quotes containing the word core:

    Individual science fiction stories may seem as trivial as ever to the blinder critics and philosophers of today—but the core of science fiction, its essence ... has become crucial to our salvation if we are to be saved at all.
    Isaac Asimov (1920–1992)