起數與+1相乘 加到 止數與-1相乘 計總和 (15026)

D2=10^SUM(LOG(C2+{-1,0,1}))/3-IFERROR(10^SUM(LOG(B2+{-1,0,1}))/3,)

另解=(C2-1)*C2*(C2+1)/3-(B2-1)*B2*(B2+1)/3