Highlight Duplicates Not Next To Each Other Using Conditional Formatting

Question

We have a list of parts in Excel in a certain order. For reasons I won't get into, we need to highlight when there are duplicates that aren't next to each other. Currently, I'm using this formula in a conditional format to do the job.

=AND(COUNTIF($A$2:$A$82,$A2)>1,$A1<>$A2,$A2<>$A3)

This mostly works well except in cases where there are pairs of duplicates like in the example below, we would want FO-1694 to be highlighted, because they aren't all next to each other. But we would not want NIS0257 to be highlighted because they are.

Currently

Ideally, this is what we want to see...

Expected

Any ideas on this could be achieved using conditional formatting?

_{Note: I have directly posted this from a past post on the SuperUser Forum (Link) as I am in need of this EXACT conditional formatting for the EXACT same circumstances. I do not take credit for the construction of this post, but only hope to obtain an answer for a question that previously went unanswered.}

Answer 1

Use this formula:

=NOT(AND(A2=OFFSET(A2,COUNTIF($A2:$A$82,A2)-1,0),A2=OFFSET(A2,-(COUNTIF($A$2:$A2,A2)-1),0)))

If changing the range then make sure to pay attention to what is marked as absolute and relative.