---
id: 5900f4b11000cf542c50ffc3
challengeType: 5
title: 'Problem 324: Building a tower'
---
## Description
Let f(n) represent the number of ways one can fill a 3×3×n tower with blocks of 2×1×1. You're allowed to rotate the blocks in any way you like; however, rotations, reflections etc of the tower itself are counted as distinct.
For example (with q = 100000007) :f(2) = 229,f(4) = 117805,f(10) mod q = 96149360,f(103) mod q = 24806056,f(106) mod q = 30808124.
Find f(1010000) mod 100000007.
## Instructions
## Tests
```yml
tests:
- text: euler324() should return 96972774.
testString: 'assert.strictEqual(euler324(), 96972774, "euler324() should return 96972774.");'
```
## Challenge Seed
```js
function euler324() {
// Good luck!
return true;
}
euler324();
```