I don't understand why you would say "each have the 
possibility of being the sixth digit".  Are these to
be combinations (where order is not important?) Or are
they permutations (where order is important).  Since
"sixth digit" specifies a particular order, it would
seem that you mean permutations rather than combinations.
If you can be more explicit in the thank-you note form
below as to what you want, I will get back to you by 
email.  Try to state the exact instructions word-for-word
as they are given.

Edwin