The Fibonacci sequence is defined as
*F _{n} = F_{n-1} + F_{n-2}*, with

An interesting way to visualise Fibonacci numbers is to start off with two *1x1* squares, and then combine their side lengths to draw a new square, *2x2*. This can be continued ad infinitum to form the Fibonacci spiral.

The ratio of successive Fibonacci numbers approaches the golden ratio, *φ*, as *n* increases.

*F _{n} / F_{n-1} = *

- Fibonacci Numbers and the Golden Section by Dr. Ron Knott
- Fibonacci number on Wikipedia

© Jason Davies 2012.