---
id: 5900f3ef1000cf542c50ff01
challengeType: 5
title: 'Problem 129: Repunit divisibility'
---
## 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(6) = 111111.
Given that n is a positive integer and GCD(n, 10) = 1, it can be shown that there always exists a value, k, for which R(k) is divisible by n, and let A(n) be the least such value of k; for example, A(7) = 6 and A(41) = 5.
The least value of n for which A(n) first exceeds ten is 17.
Find the least value of n for which A(n) first exceeds one-million.
## Instructions
## Tests
```yml
tests:
- text: euler129() should return 1000023.
testString: assert.strictEqual(euler129(), 1000023);
```
## Challenge Seed
```js
function euler129() {
// Good luck!
return true;
}
euler129();
```