here is a correction ......

Actually so that you can copy the formula to any row
=MID(CELL("ADDRESS",A$1),2,LEN(CELL("address",A$1) )-3)

To mirror the column letters on another row.
=MID(CELL("ADDRESS",A1),2,LEN(CELL("address",A1))-3)
starting from column A and use fill-handle to copy to the right.