Try this...

Data in the range A2:A11

D1 = S
C2:Cn = 1,2,3,4,5 etc

Enter this array formula** in D2 and copy down as needed:

=SUM(IF(FREQUENCY(IF(A$2:A$11=D$1,ROW(A$2:A$11)),I F(A$2:A$11<D$1,ROW(A$2:A$11)))=C2,1))

** array formulas need to be entered using the key combination of
CTRL,SHIFT,ENTER (not just ENTER). Hold down both the CTRL key and the SHIFT
key then hit ENTER.

This is what the output will be:

...........C..........D
1.....................S
2........1...........0
3........2...........2
4........3...........1
5........4...........0
6........5...........0



--
Biff
Microsoft Excel MVP


"Demosthenes" wrote in message
...
For example, suppose you have the following data:

P
S
S
P
S
S
S
P
S
S

and you want to count how many "S"s repeat after each "P." That is, you're
looking for output:

"2s" = 2
"3s" = 1

Is there any way to write a function to do that?