Hi I have a long array with case numbers that look like this

123456
123456
123456
135790
856874
154670
154670

These array are drawn from a table with a formula and are found using the formula FindNumber which I’ve defined in the name manager

I want to be able to look at this array (which is wholly located in cell B2) and return the following array

123456 
154670

as the elements in the array that have duplicate values

I can do this if I separate it into three parts, with the first part being the formula that gets the array, the second in the next column over being the following formula

=N(COUNTIF($B$2#, $B2)>1)

copied down the length of the original array, generating a list of numbers based on hoow many times the original values are located in the array and finishing it off with the formula

= unique(filter(A2#, B2:B267=1))

But I am essentially running into the constraints of excel doing calculations within formulas.

I’ve tried to do step 2 through something along the lines of

= countif(FindNumber, index(FindNumber, 1))

To at least try to find it for the first number, with maybe being able to copy it down, but I have hit a wall. I am not looking for a VBA solution.