Hi,
Please help.
I have a colun with repeating values, a second column that counts
these repeating values; formula is (=countif($a$1:$a$4000,a1). I am
looking for a third column that can then identified the repeating
values uniquely in column A or B.
Let me demonstrate in an example. (Note that I don't know how to
calculate column C, it's what I would like to achive. It would then
help me sort for only values of 1 in column C)

A B C
A005 2 1
A005 2
A006 2 1
A006 2
A009 4 1
A009 4
A009 4
A009 4

I hope to find the formula for column C.

thanks.