freeCodeCamp/curriculum/challenges/spanish/08-coding-interview-prep/project-euler/problem-407-idempotents.spanish.md

---
id: 5
localeTitle: 5900f5041000cf542c510016
challengeType: 5
title: 'Problem 407: Idempotents'
---

## Description
<section id='description'> 
Si calculamos a2 mod 6 para 0 ≤ a ≤ 5 obtenemos: 0,1,4,3,4,1. 


El valor más grande de a tal que a2 ≡ a mod 6 es 4. 
Llamemos a M (n) el valor más grande de a &lt;n tal que a2 ≡ a (mod n). 
Entonces M (6) = 4. 


Encuentra ∑M (n) para 1 ≤ n ≤ 107. 
</section>

## Instructions
<section id='instructions'> 

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>euler407()</code> debe devolver 39782849136421.
    testString: 'assert.strictEqual(euler407(), 39782849136421, "<code>euler407()</code> should return 39782849136421.");'

```

</section>

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

<div id='js-seed'>

```js
function euler407() {
  // Good luck!
  return true;
}

euler407();
```

</div>



</section>

## Solution
<section id='solution'>

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