Find the solution of $4x^2y'' - 4 x^2y' + y = 0, \, x>0$
of the form

$y_1 = x^r(1 + c_1 x + c_2 x^2 + c_3 x^3 + \cdots)$

Enter

$r =$
$c_1 =$
$c_2 =$
$c_3 =$