4. A sequence \(a _ { 1 } , a _ { 2 } , a _ { 3 } , \ldots\) is defined by
$$\begin{aligned}
& a _ { 1 } = 3
& a _ { n + 1 } = 3 a _ { n } - 5 , \quad n \geqslant 1 .
\end{aligned}$$
- Find the value of \(a _ { 2 }\) and the value of \(a _ { 3 }\).
- Calculate the value of \(\sum _ { r = 1 } ^ { 5 } a _ { r }\).