The difference equation approach (computationally fastest) can be used to derive a elegant closed form solution that relates to the golden ratio.<p>Fn=(1+√5)^n−(1−√5)^n\2^n√5<p>This deravation is pretty accessable and if you want to show off in code tests :)<p><a href="http:&#x2F;&#x2F;www.cut-the-knot.org&#x2F;proofs&#x2F;BinetFormula.shtml" rel="nofollow">http:&#x2F;&#x2F;www.cut-the-knot.org&#x2F;proofs&#x2F;BinetFormula.shtml</a>