SPOJ DIVCNT2 - Counting Divisors (square)
题目描述:求∑i=1nσ0(i2)\sum_{i=1}^n\sigma_0(i^2)i=1∑nσ0(i2)其中σ0\sigma_0σ0表示约数个数,n≤1012n\le10^{12}n≤1012,时间限制20s题目分析:σ0(i)=∑d∣iσ0(i2)=∑d∣i2ω(d)\large\sigma_0(i)=\sum_{d|i}\\\sigma_0(i^2)=\sum_{d|i}2^{...