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30-seconds-of-code/snippets/fibonacciCountUntilNum.md
2017-12-27 17:05:21 +02:00

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### fibonacciCountUntilNum
Returns the number of fibonnacci numbers up to `num`(`0` and `num` inclusive).
Use a mathematical formula to calculate the number of fibonacci numbers until `num`.
```js
const fibonacciCountUntilNum = num =>
Math.ceil(Math.log(num * Math.sqrt(5) + 1 / 2) / Math.log((Math.sqrt(5) + 1) / 2));
```
```js
fibonacciCountUntilNum(10) // 7
```