Find $n$ such that $1 + \frac{i^{(n)}}{n} = (1 + \frac{i^{(3)}}{3}) / (1 + \frac{i^{(5)}}{5})$ where $i^{(3)}$, $i^{(5)}$, $i^{(n)}$ all produce the same effective rate of interest.
$n$ =