The Nine Billion Names Of God by Arthur C. Clarke

A group of Tibetan monks, convinced that the purpose of the universe is to list all nine billion names of God, hire two Western technicians to automate the tedious work with a modern computer; once the program runs and the final names are printed, the monks are content while the technicians leave the monastery and watch in uneasy silence as the stars begin to go out, suggesting the completion of a cosmic plan.