二項重複計 1 計總數 (12768)

F2=SUMPRODUCT((B$2:B$22=E2)/COUNTIFS(B:B,B$2:B$22,C:C,C$2:C$22))

另解=SUMPRODUCT((MATCH(B$2:B$22&C$2:C$22,B$2:B$22&C$2:C$22,)=ROW($1:$21))*(B$2:B$22=E2))