Evaluate the indefinite integral as a power series:

Indefinite Integral of arctan(x^2)dx

Find the first five non-zero terms of power series representation centered at x=0

What is the radius of convergence?

Ive gotten the problem to the point where the integral equals: x^3/3-x^7/21+x^11/55-x^15/105+x^19/171...

but Ive been stuck and confused as to how I use that to find the first five nonzero terms. Can anyone help me with this? Also, I got it to where the general expression is SIgma n=0 to infinity (-1)^n * (x^2)^(4n+3)/((2n+1)*(4n+3)) + C

Am I on the right track so far? If not where am I going wrong?