Sum square difference: https://projecteuler.net/problem=6

sum-square-difference.py

#!/usr/bin/python3

import argparse


def sum_of_sequence(n):
    return n * (n + 1) / 2


def sum_of_squares_of_sequence(n):
    return n * (n + 1) * (2 * n + 1) / 6


parser = argparse.ArgumentParser(description='Difference between sum of squares and square of sum.')
parser.add_argument('n')

args = parser.parse_args()

n = int(args.n)

print(sum_of_sequence(n) ** 2 - sum_of_squares_of_sequence(n))