\[ \boxed { x \left ( {x}^{2}+1 \right ) {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) +{x}^{2}y \left ( x \right ) =0} \]
Mathematica: cpu = 0.006001 (sec), leaf count = 17 \[ \left \{\left \{y(x)\to \frac {c_1}{\sqrt {x^2+1}}\right \}\right \} \]
Maple: cpu = 0.0 (sec), leaf count = 13 \[ \left \{ y \left ( x \right ) ={{\it \_C1}{\frac {1}{\sqrt {{x}^{2}+1}}} } \right \} \]