2,3,4,5,6,7,8,9的最小公倍数是：8*5*7*9=2520,所以 1/2=1260/25201/3=840/25201/4=630/25201/5=504/25201/6=420/25201/7=360/25201/8=315/25201/9=280/25201260+840+630+504+420+360+315+280=4609所以1/2+1/3+1/4+1...