https://www.wolframalpha.com/input/?i=Sum%5BBinomial%5B1000%2C+r%5D+%283%2F10%29%5Er+%287%2F10%29%5E%281000+-+r%29%2C+%7Br%2C+330%2C+1000%7D%5D&;lang=ja

0.021581844295845248882986311033030824174678492692266322905...