2018-09-30 22:01:58 +00:00
---
id: 5900f4d01000cf542c50ffe2
challengeType: 5
title: 'Problem 355: Maximal coprime subset'
---
## Description
< section id = 'description' >
Define Co(n) to be the maximal possible sum of a set of mutually co-prime elements from {1, 2, ..., n}. For example Co(10) is 30 and hits that maximum on the subset {1, 5, 7, 8, 9}.
2018-10-08 00:01:53 +00:00
You are given that Co(30) = 193 and Co(100) = 1356.
2018-09-30 22:01:58 +00:00
Find Co(200000).
< / section >
## Instructions
< section id = 'instructions' >
< / section >
## Tests
< section id = 'tests' >
```yml
2018-10-04 13:37:37 +00:00
tests:
- text: < code > euler355()</ code > should return 1726545007.
2018-10-20 18:02:47 +00:00
testString: assert.strictEqual(euler355(), 1726545007, '< code > euler355()< / code > should return 1726545007.');
2018-09-30 22:01:58 +00:00
```
< / section >
## Challenge Seed
< section id = 'challengeSeed' >
< div id = 'js-seed' >
```js
function euler355() {
// Good luck!
return true;
}
euler355();
```
< / div >
< / section >
## Solution
< section id = 'solution' >
```js
// solution required
```
< / section >