Show that the sequence defined by `a_n=2n^2+1` is not an A.P.

Explanation

To show that the sequence defined by \( a_n = 2n^2 + 1 \) is not an arithmetic progression (A.P.), we need to check if the common difference between consecutive terms is constant.

### Step-by-Step Solution:

1. **Define the Sequence:**
The sequence is given by \( a_n = 2n^2 + 1 \).

2. **Find the First Few Terms:**
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