yea , after posting the question it kind of hit me too. I recall from information theory that something like this is maybe not possible. some other information that i can give to you is : the numbers are always ordered (from smallest to largers). numbers are uniformly distributed and usually there are about 50 numbers in the array.

ps is it possible maybe to tahe only first 8 bits for numbers 1-8 and then use the generated bit-string as a key for encoding next 8 bits and then repeate this recursivly ... hm ... i cannot see it ....