Definition:Divisor Count Function

Let $$n$$ be an integer such that $$n \ge 2$$.

The tau function $$\tau \left({n}\right)$$ is defined on $$n$$ as being the total number of positive integer divisors of $$n$$.

That is:
 * $$\tau \left({n}\right) = \sum_{d \backslash n} 1$$

where $$\sum_{d \backslash n}$$ is the sum over all divisors of $n$.