Farey sequences

Hi

has anyone coded up Farey sequences?

[
The Farey sequence of order "n"  is the set of  rational numbers i/j
with (i,j)=1 such that 0 <= i,j <= n; the sequence is ordered from 
lowest to highest.
Thus

Farey_4 = {0/1 , 1/4 , 1/3 , 1/2 , 2/3 , 3/4 , 1/1}
]

My motivation is unimodular transformations: I need to systematically
generate 2-by-2 integer matrices with determinant 1, and Farey sequences
seem to be the best way to do this.




--
Robin Hankin
Uncertainty Analyst
Southampton Oceanography Centre
European Way, Southampton SO14 3ZH, UK
  tel  023-8059-7743