I need help in a bonus problem

hi guys it's me you helped me last time in my bonus problem(thank's for that) i need help again naw please it's a two marks bonus problem:

solve using power series:
(x^2)(y")+y=0

after solving it i stoped at :

an[n^2-n+1]=0

$$y= \sum_{n=0}^{\infty} a_nx^{n+i}$$