Given an array, return the element at which the "pattern"
breaks.
For example, in the array [2,4,6,8,11,13,15,17], the algorithm
should return 11 because the difference between every previous node
was 2, and the difference between 8 and 11 is 3.
PLEASE USE DIVIDE AND CONQUER. Thank you.
Python please or just a description of the algorithm