[RESOLVED] need formula - unique combination

[billwagnon]

A number is generated by adding any combination of a,b,c,d, or e where a = 1, b = 2, c = 4, d = 8, e = 16.

What I want to determine from the number is which of the combinations was used.

Is there a simple way to do this with a formula or a loop (instead of a select case for every possible result)?

I know if it's odd then it must include "a" but I can't get past that step.

I have made a spreadsheet of possible values:

a       b       c       d        e      value
 
1                   1
    2               2
1   2               3
        4           4
1       4           5
    2   4           6
1   2   4           7
            8       8
1           8       9
    2       8       10
1   2       8       11
        4   8       12
1       4   8       13
    2   4   8       14
1   2   4   8       15
                16  16
1               16  17
    2           16  18
1   2           16  19
        4       16  20
1       4       16  21
    2   4       16  22
1   2   4       16  23
            8   16  24
1           8   16  25
    2       8   16  26
1   2       8   16  27
        4   8   16  28
1       4   8   16  29
    2   4   8   16  30
1   2   4   8   16  31

Thanks for your help!