The Fibonacci sequence is a series of numbers where a number is found by adding up the two numbers before it. Starting with 0 and 1, the sequence goes 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, and so forth. Written as a rule, the expression is xn<span> = x</span>n-1<span> + x</span>n-2<span>. </span>A recursive sequence<span> , also known as a recurrence</span>sequence<span>, is a </span>sequence<span> of numbers indexed by an integer and generated by solving a recurrence equation. The terms of a </span>recursive sequences<span> can be denoted symbolically in a number of different notations, such as , , or f[ ], where is a symbol representing the </span>sequence<span>. </span>