Terry,

I don't know of a formula that will do it but this macro. Right click the
sheet tab, view code and paste this in.

Put your numbers in column A start ing in A1 and run the code. The
combinations will be output to column B.

Sub combinations()
last = Cells(Rows.Count, "A").End(xlUp).Row
   For I = 1 To last - 2
       For J = I + 1 To last - 1
           For K = J + 1 To last
               Cells(L + 1, 2) = Cells(I, 1) & Cells(J, 1) & Cells(K, 1)
               L = L + 1
           Next
       Next
   Next
End Sub

Mike

Another play is to use Myrna Larson's power subroutine
to generate the combinations ..

Take away this implemented sample from my archives:
http://www.savefile.com/files/518493
MyrnaLarson_Combination_Permutation.xls
(full details inside, ready to run

In the sample file,
In Sheet1,
1. Enter the letter C or P in A1 (C = combinations, P = permutations), ie
enter: C
2. Enter the number of items involved per combo in A2, ie enter: 3
3. Enter/List the 6 items in A3 down, ie list in A3:A8  :1, 2, ... 6
4. Select A1 (this cell selection is required), then click the button
ListPermutations to run the sub ListPermutations
5. The results will be written to a new sheet (just to the left),and appear
like below, in a zig-zag manner* until all combos are exhausted:
*if it exceeds the rows limit of 65536 in xl97 to xl2003

1, 2, 3
1, 2, 4
1, 2, 5
1, 2, 6
...
4, 5, 6

Go easy when you *ramp* up the generation ...
eg a "Pick 6 out of 45" run works out to a staggering:
=COMBIN(45,6) = 8,145,060 combinations
so almost half** an entire sheet would be populated

**A single sheet in xl97 to xl2003 houses:
=65536 rows x 256 cols = 16,777,216 cells

The sub would certainly need time to complete generation