\[ (x+3) x^2 y^{(3)}(x)-3 (x+2) x y''(x)+6 (x+1) y'(x)-6 y(x)=0 \] ✓ Mathematica : cpu = 0.0236776 (sec), leaf count = 65
DSolve[-6*y[x] + 6*(1 + x)*Derivative[1][y][x] - 3*x*(2 + x)*Derivative[2][y][x] + x^2*(3 + x)*Derivative[3][y][x] == 0,y[x],x]
\[\left \{\left \{y(x)\to \frac {1}{4} c_1 \left (x^3-3 x^2+3 x+3\right )+\frac {1}{2} c_2 \left (-x^3+3 x^2-x-1\right )+\frac {1}{8} c_3 \left (3 x^3-5 x^2+x+1\right )\right \}\right \}\] ✓ Maple : cpu = 0.119 (sec), leaf count = 19
dsolve((x+3)*x^2*diff(diff(diff(y(x),x),x),x)-3*x*(x+2)*diff(diff(y(x),x),x)+6*(1+x)*diff(y(x),x)-6*y(x)=0,y(x))
\[y \left (x \right ) = x^{3} c_{2}+c_{1} x^{2}+c_{3} x +c_{3}\]