Fibonacci sequence

The Fibonacci sequence is a series of numbers in which each number is the sum of the two preceding it (the first two terms are simply 1). The first few terms are $1,1,2,3,5,8,13,21,34,55,...$ . Ratios between successive terms, $\frac{1}{1}$ , $\frac{2}{1}$ , $\frac{3}{2}$ , $\frac{5}{3}$ , $\frac{8}{5}$ , tend towards the limit phi.