The number of divisors function $\tau:\mathbb N\to\mathbb N$ is an arithmetic function counting how many divisors a given number $n\in\mathbb N$ has. In the sum notation notation, the $\tau$ function can be written as $$\tau(n):=\sum_{d \mid n}1\quad\quad\forall n > 0.$$
The $\tau$ function can be visualized using SageMath. If you click on the evaluate button, you will see the values of $\tau(n)$ for $n=1,\ldots,100.$
Examples: 1
Proofs: 2 3
Propositions: 4
