Let $a_1, a_2, \dots, a_n$ be $n \ge 1$ distinct odd integers with no prime factors $\gt 5$.
Show that
$$ \sum_{i=1}^{n} \dfrac{1}{a_n} \lt \frac{15}{8}$$
[Solution]
Let $a_1, a_2, \dots, a_n$ be $n \ge 1$ distinct odd integers with no prime factors $\gt 5$.
Show that
$$ \sum_{i=1}^{n} \dfrac{1}{a_n} \lt \frac{15}{8}$$
[Solution]
