I tried finding it's convergence by converting it into exponential series using first by ratio test and then by Raabe's test and reached closer to the answer but not the exact answer.
$$\frac{a+x}{1!} + \frac{(a+2x)^2}{2!} + \frac{(a+3x)^3}{3!} + \ldots$$
Answer: Convergence for $x< 1/e$ and divergence for $x>1/e$ and $x=1/e$.
Please give solution if anybody has done this question.
