Consider an A.P.: a_1, a_2, …, a_n; a_1>0. If a_2-a_1=-3/4, a_n =1/4 a_1, and Σ_i =1^n a_i =525/2, then Σ_i =1^17 a_i is equal to

Consider an A.P.: $\displaystyle a_1, a_2, \ldots, a_{\mathrm{n}} ; a_1>0$. If $\displaystyle a_2-a_1=\frac{-3}{4}, a_{\mathrm{n}}=\frac{1}{4} a_1$, and $\displaystyle \sum_{\mathrm{i}=1}^{\mathrm{n}} a_{\mathrm{i}}=\frac{525}{2}$, then $\displaystyle \sum_{\mathrm{i}=1}^{17} a_{\mathrm{i}}$ is equal to