FORMULA function
FORMULA displays the formula of a formula cell at any position. The formula is returned as a string in the reference position. If no formula cell can be found, or if the presented argument is not a reference, the error value #N/A is set.
Syntax
FORMULA(reference)
Example
The cell A8 contains the result of a formula having the value 23. You can use the FORMULA function in cell A1 to display the formula in cell A8.