---
id: 5900f4181000cf542c50ff2b
challengeType: 5
title: 'Problem 172: Investigating numbers with few repeated digits'
---
## Description
How many 18-digit numbers n (without leading zeros) are there such that no digit occurs more than three times in n?
## Instructions
## Tests
```yml
tests:
- text: euler172() should return 227485267000992000.
testString: assert.strictEqual(euler172(), 227485267000992000, 'euler172() should return 227485267000992000.');
```
## Challenge Seed
```js
function euler172() {
// Good luck!
return true;
}
euler172();
```