\[ \boxed { 4\,x{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) - \left ( x+a \right ) y \left ( x \right ) =0} \]
Mathematica: cpu = 0.094512 (sec), leaf count = 78 \[ \left \{\left \{y(x)\to \frac {1}{4} c_2 e^{-x/2} x \, _1F_1\left (\frac {1}{128} (-32 (-a-4 i)-128 i)+1;2;x\right )+\frac {1}{4} c_1 e^{-x/2} x U\left (\frac {1}{128} (-32 (-a-4 i)-128 i)+1,2,x\right )\right \}\right \} \]
Maple: cpu = 0.094 (sec), leaf count = 21 \[ \left \{ y \left ( x \right ) ={\it \_C1}\,{{\sl M}_{-{\frac {a}{4}},\,{ \frac {1}{2}}}\left (x\right )}+{\it \_C2}\,{{\sl W}_{-{\frac {a}{4}},\, {\frac {1}{2}}}\left (x\right )} \right \} \]