def euler_028():
    total = 1
    current_corner = 3
    for n in range(3, 1002, 2):
        total += 4 * current_corner + 6 * (n - 1)
        current_corner += 4 * n - 2
    return total


if __name__ == "__main__":
    print("e028.py: {}".format(euler_028()))
    assert(euler_028() == 669171001)