We derive an exact recursion formula for the calculation of thermodynamic f
unctions of finite systems obeying Bose-Einstein statistics. The formula is
applicable for canonical systems where the particles can be treated as non
interacting in some approximation, e.g., like Bose-Einstein condensates in
magnetic traps. The numerical effort of our computation scheme grows only l
inearly with the number of particles. As an example, we calculate the relat
ive ground-state fluctuations and specific heats for ideal Bose gases with
a finite number of particles enclosed in containers of different shapes. [S
1050-2947(99)04203-1].