Power Series Solution

Find the second value in terms of $a_{0}$ for the following differential equation (Eq. A) using the following assumption,

$y(x)= \sum_{k=0}^\infty\ a_{k}x^{k}.$

$\frac{d^2 y}{dx^2}+x\frac{dy}{dx}+y(x)=0 (Eq. A)$