Find the sum to n terms of the series :`5^2+6^2+7^2+dotdotdot+20^2`

Explanation

To find the sum of the series \(5^2 + 6^2 + 7^2 + \ldots + 20^2\), we can follow these steps:

### Step 1: Identify the series
The series we need to sum is from \(5^2\) to \(20^2\). This can be expressed as:
\[ \sum_{k=5}^{20} k^2 \]

...