DivisorSum

$$\sum_{k \mid n} f(k)$$

The sum of $f(k)$ taken over all positive integers $k$ dividing the integer $n$.

$$\sum_{k \mid n,\, P(k)} f(k)$$

The sum of $f(k)$ taken over all positive integers $k$ dividing the integer $n$ and satisfying the predicate $P(k)$.

Last updated: 2020-03-06 00:22:16