freeCodeCamp/curriculum/challenges/english/08-coding-interview-prep/project-euler/problem-442-eleven-free-integers.english.md

---
id: 5900f5271000cf542c510039
challengeType: 5
title: 'Problem 442: Eleven-free integers'
---

## Description
<section id='description'>
An integer is called eleven-free if its decimal expansion does not contain any substring representing a power of 11 except 1.

For example, 2404 and 13431 are eleven-free, while 911 and 4121331 are not.

Let E(n) be the nth positive eleven-free integer. For example, E(3) = 3, E(200) = 213 and E(500 000) = 531563.

Find E(1018).
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>euler442()</code> should return 1295552661530920200.
    testString: assert.strictEqual(euler442(), 1295552661530920200, '<code>euler442()</code> should return 1295552661530920200.');

```

</section>

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

<div id='js-seed'>

```js
function euler442() {
  // Good luck!
  return true;
}

euler442();
```

</div>



</section>

## Solution
<section id='solution'>

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