Sequences And Series

Let \(2^{\text {nd }}, 8^{\text {th }}\) and \(44^{\text {th }}\) terms of a non-constant A. P. be respectively the \(1^{\text {st }}, 2^{\text {nd }}\) and \(3^{\text {rd }}\) terms of a G. P. If the first term of the A. P. is 1, then the sum of its first 20 terms is equal to -