题目描述

Let $\sigma_0(n)$ be the number of positive divisors of $n$.

For example, $\sigma_0(1) = 1$ , $\sigma_0(2) = 2$ and $\sigma_0(6) = 4$.

Let $S_k(n) = \sum _{i=1}^n \sigma_0(i^k)$.

Given $n$ and $k$ , find $S_k(n) \bmod 2^{64}$.

## 题目描述

Let $\sigma_0(n)$ be the number of positive divisors of $n$.

For example, $\sigma_0(1) = 1$ , $\sigma_0(2) = 2$ and $\sigma_0(6) = 4$.

Let $S_k(n) = \sum _{i=1}^n \sigma_0(i^k)$.

Given $n$ and $k$ , find $S_k(n) \bmod 2^{64}$.