Properties of Fibonacci Numbers

Theorem
Let $F_k$ be the $k$th Fibonacci number.

That is, let:
 * $F_1 = 1, F_2 = 1, F_3 = 2, F_4 = 3$

For $n > 2$, values are computed using:
 * $F_n = F_{n-1} + F_{n-2}$