The Fibonacci sequence is the integer sequence: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, ... By definition, the first two numbers in the Fibonacci sequence are 0 and 1. Each subsequent number is the sum of the previous two F(n) = F(n-1) + F(n-2). n can be any positive integer and this equation will return the nth term.