freeCodeCamp/curriculum/challenges/chinese/10-coding-interview-prep/project-euler/problem-443-gcd-sequence.md

---
id: 5900f5271000cf542c51003a
challengeType: 5
videoUrl: ''
title: 问题443：GCD序列
---

## Description
<section id="description">设g（n）为如下定义的序列：g（4）= 13，g（n）= g（n-1）+ gcd（n，g（n-1）），n&gt; 4。 <p>前几个值是： </p><pre> <code>n4567891011121314151617181920... g(n)1314161718272829303132333451545560...</code> </pre><p>给出g（1 000）= 2524和g（1 000 000）= 2624152。 </p><p>找到g（1015）。 </p></section>

## Instructions
<section id="instructions">
</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>euler443()</code>应该返回2744233049300770。
    testString: assert.strictEqual(euler443(), 2744233049300770);

```

</section>

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

<div id='js-seed'>

```js
function euler443() {
  // Good luck!
  return true;
}

euler443();

```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```

/section>