1,1,2,3,5,8,13,21,34,55, 89, 144, etc.
(you can add the 0 before the one but i prefer not to.)
This sequence is found often in nature in a lot of things that form spirals such as sunflowers, spiral galaxies, spiral shells, and more.
(For the sake of keeping this kind of short I am not going to go over the Fibonacci sequence itself too much in this article, but if you would like to learn more about it before reading this article I have posted a link below.)
Not only is the Fibonacci sequence found in nature, but it is also a major factor in foreign currency exchange rates. By taking four sequential Fibonacci numbers, dividing them by one another you get the ratios 0%, 23.6%, 38.2%,61.8%.Technically 100% and 50% aren't a part of the ratio but they are added as well. (more on all of this in a link below as well.)
http://en.wikipedia.org/wiki/Fibonacci_number
http://www.scientificpapers.org/wp-content/files/1134_How_to_use_Fibonacci_retracement_to_predict_forex_market.pdf