1/1×2×3+1/2×3×4+.+1/20×21×22怎么算?

1/1×2×3+1/2×3×4+.+1/20×21×22怎么算?
1/1×2×3+1/2×3×4+.+1/20×21×22怎么算?

1/1×2×3+1/2×3×4+.+1/20×21×22怎么算?
for i=1 to 20
a=i
b=1/a*(a+1)*(a+2)
c=c+b
next i
print c
是这个意思,是FOXPRO的程序.方法是这样,不过语句可能是错的.