--description--

Consider numbers $t(n)$ of the form $t(n) = 2n^2 - 1$ with $n > 1$.

The first such numbers are 7, 17, 31, 49, 71, 97, 127 and 161.

It turns out that only $49 = 7 \times 7$ and $161 = 7 \times 23$ are not prime.

For $n ≤ 10000$ there are 2202 numbers $t(n)$ that are prime.

How many numbers $t(n)$ are prime for $n ≤ 50\,000\,000$?

--hints--

primalityOfNumbers() should return 5437849.

assert.strictEqual(primalityOfNumbers(), 5437849);

--seed--

--seed-contents--

function primalityOfNumbers() {

  return true;
}

primalityOfNumbers();

--solutions--

// solution required