Difference Of Squares

Find the difference between the sum of the squares and the square of the sums of the first N natural numbers.

The square of the sum of the first ten natural numbers is,

(1 + 2 + ... + 10)**2 = 55**2 = 3025

The sum of the squares of the first ten natural numbers is,

1**2 + 2**2 + ... + 10**2 = 385

Hence the difference between the square of the sum of the first ten natural numbers and the sum of the squares is 2640:

3025 - 385 = 2640

Running tests

$ elixir bob_test.exs

(Replace bob_test.exs with the name of the test file.)

Source

Problem 6 at Project Euler view source