In Excel I need a formula to set up a puzzle as follows:
Grid of 81 cells set up 9 rows and 9 columns.
each row and column can only have numbers 1 thru 9 each row & column.
Each row and column has to have 1,2,3,4,5,6,7,8,9 in any order as long as
each row & column has all 9 digits represented.
example: Column A and Row 1 have a common number (1 thru 9) this number
cannot be repeated in Column A or Row 1. Next row/column relates the same as
previous row/Column,

How would this formula be written?