Fibonacci sequence

Example

The Fibonacci sequence $(F_n)_{n \ge 0}$ is the sequence of natural numbers defined by $$F_0 = 0, \qquad F_1 = 1, \qquad F_{n+2} = F_{n+1} + F_n.$$ It is an example of a sequence defined by a recurrence relation, and in particular of a linear recurrence with constant coefficients. Its first terms are $$0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, \dots$$