43 lines
696 B
Markdown
43 lines
696 B
Markdown
|
---
|
|||
|
|
id: 5900f3f11000cf542c50ff03
|
|||
|
|
title: 'Problem 132: Large repunit factors'
|
|||
|
|
challengeType: 5
|
|||
|
|
forumTopicId: 301760
|
|||
|
|
dashedName: problem-132-large-repunit-factors
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
# --description--
|
|||
|
|
|
|||
|
|
A number consisting entirely of ones is called a repunit. We shall define R(k) to be a repunit of length k.
|
|||
|
|
|
|||
|
|
For example, R(10) = 1111111111 = 11×41×271×9091, and the sum of these prime factors is 9414.
|
|||
|
|
|
|||
|
|
Find the sum of the first forty prime factors of R(109).
|
|||
|
|
|
|||
|
|
# --hints--
|
|||
|
|
|
|||
|
|
`euler132()` should return 843296.
|
|||
|
|
|
|||
|
|
```js
|
|||
|
|
assert.strictEqual(euler132(), 843296);
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
# --seed--
|
|||
|
|
|
|||
|
|
## --seed-contents--
|
|||
|
|
|
|||
|
|
```js
|
|||
|
|
function euler132() {
|
|||
|
|
|
|||
|
|
return true;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
euler132();
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
# --solutions--
|
|||
|
|
|
|||
|
|
```js
|
|||
|
|
// solution required
|
|||
|
|
```
|