freeCodeCamp/curriculum/challenges/english/08-coding-interview-prep/project-euler/problem-135-same-differences.english.md

---
id: 5900f3f31000cf542c50ff06
challengeType: 5
title: 'Problem 135: Same differences'
forumTopicId: 301763
---

## Description
<section id='description'>
Given the positive integers, x, y, and z, are consecutive terms of an arithmetic progression, the least value of the positive integer, n, for which the equation, x2 − y2 − z2 = n, has exactly two solutions is n = 27:
342 − 272 − 202 = 122 − 92 − 62 = 27
It turns out that n = 1155 is the least value which has exactly ten solutions.
How many values of n less than one million have exactly ten distinct solutions?
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>euler135()</code> should return 4989.
    testString: assert.strictEqual(euler135(), 4989);

```

</section>

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

<div id='js-seed'>

```js
function euler135() {
  // Good luck!
  return true;
}

euler135();
```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```

</section>