\[ \boxed { {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) =-2\,{\frac {{\frac {\rm d}{{\rm d}x}}y \left ( x \right ) }{x}}-{\frac {{a}^{2}y \left ( x \right ) }{{x}^{4}}}=0} \]
Mathematica: cpu = 0.009501 (sec), leaf count = 25 \[ \left \{\left \{y(x)\to c_1 \cos \left (\frac {a}{x}\right )-c_2 \sin \left (\frac {a}{x}\right )\right \}\right \} \]
Maple: cpu = 0.0 (sec), leaf count = 21 \[ \left \{ y \left ( x \right ) ={\it \_C1}\,\sin \left ( {\frac {a}{x}} \right ) +{\it \_C2}\,\cos \left ( {\frac {a}{x}} \right ) \right \} \]