2018-10-10 18:03:03 -04:00
---
id: 5900f4d01000cf542c50ffe2
2021-02-06 04:42:36 +00:00
title: 'Problem 355: Maximal coprime subset'
2018-10-10 18:03:03 -04:00
challengeType: 5
2021-02-06 04:42:36 +00:00
forumTopicId: 302015
2021-01-13 03:31:00 +01:00
dashedName: problem-355-maximal-coprime-subset
2018-10-10 18:03:03 -04:00
---
2020-12-16 00:37:30 -07:00
# --description--
2018-10-10 18:03:03 -04:00
2021-02-06 04:42:36 +00:00
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}.
2018-10-10 18:03:03 -04:00
2021-02-06 04:42:36 +00:00
You are given that Co(30) = 193 and Co(100) = 1356.
2018-10-10 18:03:03 -04:00
2021-02-06 04:42:36 +00:00
Find Co(200000).
2018-10-10 18:03:03 -04:00
2020-12-16 00:37:30 -07:00
# --hints--
2018-10-10 18:03:03 -04:00
2021-02-06 04:42:36 +00:00
`euler355()` should return 1726545007.
2018-10-10 18:03:03 -04:00
```js
2020-12-16 00:37:30 -07:00
assert.strictEqual(euler355(), 1726545007);
2018-10-10 18:03:03 -04:00
```
2021-01-13 03:31:00 +01:00
# --seed--
## --seed-contents--
```js
function euler355() {
return true;
}
euler355();
```
2020-12-16 00:37:30 -07:00
# --solutions--
2020-08-13 17:24:35 +02:00
2021-01-13 03:31:00 +01:00
```js
// solution required
```