Mathematician:J. Perrot

Mathematician

 * $\displaystyle \lim_{n \mathop \to \infty} \dfrac {\map \Phi n} {n^2} = \dfrac 3 {\pi^2}$

where:


 * $\map \Phi n = \displaystyle \sum_{k \mathop = 1}^n \map \phi k$
 * $\map \phi k$ is the Euler $\phi$ function of $k$.

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