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杜教筛

i=1QQφ(i)=40539567414958\sum_{i=1}^{\text{QQ}}\varphi(i)=40539567414958

参考资料

例题

给定 TT 个正整数 nn,求 i=1nφ(i)\sum_{i=1}^n\varphi(i)i=1nμ(i)\sum_{i=1}^n \mu(i)。(T10,n231T\le10,n\le2^{31}