all arrangements of 8 letter words with 3 symbols

1. Anyone know how to use excel to generate all "8 element" arrangements of 3 symbols (has duplicates). Example: use aaaabbcc as a seed and get all possible arrangements.

2. Rank those arrangements. rank(aaaabbcc) = 1,
... rank(aaaaccbb) = 5 ...

3. unrank(234) = aacbacba (I don't know what it really is or how to do it?)