Rank: ? (171)
Member #: 11947

Fn <= phi^(n-1)

Fn is the n'th fibonacci number, and phi is (1 + sqrt(5) )/2.

Some notes about the number phi, it is defined by the greeks using ratios of line segments, but for this problem it is more usefull to describe it this way:

1 + phi = phi^2

So phi, is a number, when squared equals itself plus one.