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Feat: add new Markdown parser (#39800)

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and change all the challenges to new `md` format.
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Oliver Eyton-Williams
2020-11-27 19:02:05 +01:00
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curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-245-coresilience.md
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@ -1,46 +1,27 @@
---
id: 5900f4621000cf542c50ff74
challengeType: 5
title: 'Problem 245: Coresilience'
challengeType: 5
forumTopicId: 301892
---
## Description
<section id='description'>
# --description--
We shall call a fraction that cannot be cancelled down a resilient fraction. Furthermore we shall define the resilience of a denominator, R(d), to be the ratio of its proper fractions that are resilient; for example, R(12) = 4⁄11.
The resilience of a number d > 1 is then
φ(d)d − 1
, where φ is Euler's totient function.
We further define the coresilience of a number n > 1 as C(n)= 
n − φ(n)n − 1.
The coresilience of a prime p is C(p)
= 
1p − 1.
Find the sum of all composite integers 1 < n ≤ 2×1011, for which C(n) is a unit fraction.
</section>
The resilience of a number d > 1 is then φ(d)d − 1 , where φ is Euler's totient function. We further define the coresilience of a number n > 1 as C(n)= n − φ(n)n − 1. The coresilience of a prime p is C(p) = 1p − 1. Find the sum of all composite integers 1 &lt; n ≤ 2×1011, for which C(n) is a unit fraction.
## Instructions
<section id='instructions'>
# --hints--
</section>
## Tests
<section id='tests'>
```yml
tests:
- text: <code>euler245()</code> should return 288084712410001.
testString: assert.strictEqual(euler245(), 288084712410001);
`euler245()` should return 288084712410001.
```js
assert.strictEqual(euler245(), 288084712410001);
```
</section>
# --seed--
## Challenge Seed
<section id='challengeSeed'>
<div id='js-seed'>
## --seed-contents--
```js
function euler245() {
@ -51,17 +32,8 @@ function euler245() {
euler245();
```
</div>
</section>
## Solution
<section id='solution'>
# --solutions--
```js
// solution required
```
</section>