## Find Expression

### Instructions

Create a function named `findExpression` that takes a `number` as parameter and returns a `string`.

- 2 constant variables will be made available to your function: `add4` and `mul2`.
- Your goal is to try to find a sequence, starting from the number 1, and repeatedly either adding 4 or multiplying by 2, to produce the number given as a parameter.
- If the number can not be reached you should return `undefined`

For example, for the number `8`, you must first multiply by 2 twice, and then add 4. Your function should return something like: `1 *2 *2 +4`.

### Notions

- [Loops](https://nan-academy.github.io/js-training/examples/loops.js)
- [Recursion](https://nan-academy.github.io/js-training/examples/recursion.js)

### Code provided

> The provided code will be added to your solution, and does not need to be submitted.

```js
const add4 = '+4'
const mul2 = '*2'
```
