> A series of numbers in which each number ( Fibonacci number ) is the sum of the two preceding numbers. In this exercise, the series starts from 1, 1, 2, 3, 5, 8... but it can also start from 0, 1, 1, 2, 3, 5...
> To learn more about Fibonacci sequences, go to: https://en.wikipedia.org/wiki/Fibonacci_sequence