A recursive sequence is an ordered list of numbers defined by a starting value and a rule. You generate the sequence by applying the rule to the starting value, applying the rule again to the resulting value, and then repeating this process.
A recursive formula always has two parts:
1. the starting values.
2. the recursion equation for an as a function of the terms before it.
1, 1, 2, 3, 5, 8, ... is a recursive sequence, where: