fix(challenge-md): Fix file names and preserve challenge order in meta.json

curriculum/challenges/en/08-coding-interview-prep/project-euler/problem-443-gcd-sequence.en.md

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+---
+id: 5900f5271000cf542c51003a
+challengeType: 5
+title: 'Problem 443: GCD sequence'
+---
+
+## Description
+<section id='description'>
+Let g(n) be a sequence defined as follows:
+g(4) = 13,
+g(n) = g(n-1) + gcd(n, g(n-1)) for n > 4.
+
+The first few values are:
+
+    n4567891011121314151617181920...
+    g(n)1314161718272829303132333451545560...
+
+
+You are given that g(1 000) = 2524 and g(1 000 000) = 2624152.
+
+Find g(1015).
+</section>
+
+## Instructions
+<section id='instructions'>
+
+</section>
+
+## Tests
+<section id='tests'>
+
+```yml
+- text: <code>euler443()</code> should return 2744233049300770.
+  testString: 'assert.strictEqual(euler443(), 2744233049300770, ''<code>euler443()</code> should return 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>