1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...

By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.$F_{n} = F_{n-1} + F_{n-2} \text{ for } n \geq 2$

$F_{0} = 1, F_{1} = 2$

we simply calculate each fibonacci up to (and possibly including) 4 million. For each fibonacci number, we add it to the total if it is even.

The full `utils`

module can be found on GitHub here