Notice that if 1 is subtracted from each term of the sequence, we get the sequence \(1, 4, 9, 16, 25, \cdots\) which are all perfect squares.
The terms of the sequence \(2, 5, 10, 17, 26, \cdots\) are all one more than a perfect square.
The general formula for the \(n\)-th term is \(c_n = 1 + n^2\).