---
id: 5900f4451000cf542c50ff57
challengeType: 5
title: 'Problem 216: Investigating the primality of numbers of the form 2n2-1'
videoUrl: ''
localeTitle: ''
---

## Description
undefined

## Instructions
undefined

## Tests
<section id='tests'>

```yml
tests:
  - text: ''
    testString: 'assert.strictEqual(euler216(), 5437849, "<code>euler216()</code> should return 5437849.");'

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='js-seed'>

```js
function euler216() {
  // Good luck!
  return true;
}

euler216();

```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```
</section>