I have been using COUNTIF(A:A,A#) to check for doubles for a while now. The
formula works fine for small ranges of numbers, but really starts to lag
after 4000 numbers or more. Well, now I am having to deal with serial number
ranges of 10-60000 and my formula is no longer practical.
Is there a faster way to identify multiple (up to 5 or so) occurences of the
same number(with alpha characters) in a column?

Thanks,