I require unique random numbers to be generated per the number of contestants on drawsheets. The array formula I have is eg. for 20 competitors =LARGE(ROW($1:$20)*NOT(COUNTIF($B$2:B2,ROW($1:$20))),RANDBETWEEN(1,21-ROW(A1))). For 10 competitors, I have to manually change the ROW formula to ROW ($1:$20) and the random selection to RANDBETWEEN (1,11-ROW(a1). How can improve this formula to automatically use the number of contestants per draw sheet to adjust the ROW maximum and RANDBETWEEN formula?