Find the sum of the first n terms of the series : `3 + 7 + 13 +21 + 31 +.....`

Explanation

To find the sum of the first \( n \) terms of the series \( 3 + 7 + 13 + 21 + 31 + \ldots \), we first need to identify the pattern in the series.

### Step 1: Identify the series pattern
The given series is:
- \( a_1 = 3 \)
- \( a_2 = 7 \)
- \( a_3 = 13 \)
- \( a_4 = 21 \)
...