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On the identity $\sum_{n \leq x} \frac{1}{n} \sum_{k \leq \frac{x}{n}} \frac{\mu(k)}{k}=1$

Writing $m=nk$, \begin{align*} \sum_{n \le x} \frac{1}{n} \sum_{k \le x/n} \frac{\mu(k)}{k} &= \sum_{nk\le x} \frac1{nk} \mu(k) = \sum_{m\le x} \frac1m \sum_{k\mid m} \mu(k) = \sum_{m\le x} \...
Greg Martin's user avatar
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2 votes
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Asymptotic order of $\sum_{n>x}\frac{\mu (n)\ln n}{n^2}$

Your current bound $\sum_{n>x} n^{-3/2}$ would yield $O(x^{-1/2})$, which goes to $0$ slower than $O(\ln(x)/x)$. But you can get a better bound with a simple trick. Observe that $$\left|\sum_{n>...
Hanul Jeon's user avatar
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Software for computing Möbius function of a poset

Sage and Macaulay2 are open source and provide functionality for computing the Möbius function of a partially ordered set. Sage has the method ...
Aaron Dall's user avatar
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