Question 152
Determine with proof, a simple closed form expression for
$$
\sum_{d \mid n} \phi(d) \tau\left(\frac{n}{d}\right)
$$
$$
\sum_{d \mid n} \phi(d) \tau\left(\frac{n}{d}\right)
$$
MathNet 2007-part-03 — 185 problems (EN–VI) Question 152
Math Olympiad Vault · MathNet 2007-part-03 — 185 problems (EN–VI)