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

1^{2} + 2^{2} + ... + 10^{2} = 385

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

(1 + 2 + ... + 10)^{2} = 55^{2} = 3025

Hence the difference between the sum of the squares of the first ten natural numbers and the square of the sum is 3025

385 = 2640.

Find the difference between the sum of the squares of the first one hundred natural numbers and the square of the sum.

Remember Sigma(n) = (n*(n+1))/2

and Sigma(n^2) = (n*(n+1)*(2n+1))/6

Equating them w.r.t to given problem = Sigma(n)^2 - Sigma(n^2) is

**(n * ((n * n) - 1) * ((3 * n) + 2)) / 12**

Answer to the Problem is : **25164150**

```
using System;
namespace ProjectEuler
{
class SquareAndSum
{
```