---
id: 5900f4591000cf542c50ff6c
challengeType: 5
title: 'Problem 237: Tours on a 4 x n playing board'
---

## Description
<section id='description'>
Let T(n) be the number of tours over a 4 × n playing board such that:
The tour starts in the top left corner.
The tour consists of moves that are up, down, left, or right one square.
The tour visits each square exactly once.
The tour ends in the bottom left corner.
The diagram shows one tour over a 4 × 10 board:




T(10) is 2329. What is T(1012) modulo 108?
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>euler237()</code> should return 15836928.
    testString: 'assert.strictEqual(euler237(), 15836928, "<code>euler237()</code> should return 15836928.");'

```

</section>

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

<div id='js-seed'>

```js
function euler237() {
  // Good luck!
  return true;
}

euler237();
```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```
</section>