---
id: 5900f4c71000cf542c50ffd8
challengeType: 5
title: 'Problem 346: Strong Repunits'
---

## Description
<section id='description'>
The number 7 is special, because 7 is 111 written in base 2, and 11 written in base 6 (i.e. 710 = 116 = 1112). In other words, 7 is a repunit in at least two bases b > 1.


We shall call a positive integer with this property a strong repunit. It can be verified that there are 8 strong repunits below 50:  {1,7,13,15,21,31,40,43}. Furthermore, the sum of all strong repunits below 1000 equals 15864.

Find the sum of all strong repunits below 1012.
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>euler346()</code> should return 336108797689259260.
    testString: assert.strictEqual(euler346(), 336108797689259260, '<code>euler346()</code> should return 336108797689259260.');

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='js-seed'>

```js
function euler346() {
  // Good luck!
  return true;
}

euler346();
```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```

</section>