--description--

Let $P(m,n)$ be the number of distinct terms in an $m×n$ multiplication table.

For example, a 3×4 multiplication table looks like this:

$$\begin{array}{c} × & \mathbf{1} & \mathbf{2} & \mathbf{3} & \mathbf{4} \\ \mathbf{1} & 1 & 2 & 3 & 4 \\ \mathbf{2} & 2 & 4 & 6 & 8 \\ \mathbf{3} & 3 & 6 & 9 & 12 \end{array}$$

There are 8 distinct terms {1, 2, 3, 4, 6, 8, 9, 12}, therefore $P(3, 4) = 8$.

You are given that:

$$\begin{align} & P(64, 64) = 1\,263, \\ & P(12, 345) = 1\,998, \text{ and} \\ & P(32, {10}^{15}) = 13\,826\,382\,602\,124\,302. \\ \end{align}$$

Find $P(64, {10}^{16})$.

--hints--

multiplicationTable() should return 258381958195474750.

assert.strictEqual(multiplicationTable(), 258381958195474750);

--seed--

--seed-contents--

function multiplicationTable() {

  return true;
}

multiplicationTable();

--solutions--

// solution required