\[ (-a-x) y(x)+x^2 y''(x)+x y'(x)=0 \] ✓ Mathematica : cpu = 0.0252928 (sec), leaf count = 78
DSolve[(-a - x)*y[x] + x*Derivative[1][y][x] + x^2*Derivative[2][y][x] == 0,y[x],x]
\[\left \{\left \{y(x)\to (-1)^{-\sqrt {a}} c_1 \operatorname {Gamma}\left (1-2 \sqrt {a}\right ) \operatorname {BesselI}\left (-2 \sqrt {a},2 \sqrt {x}\right )+(-1)^{\sqrt {a}} c_2 \operatorname {Gamma}\left (2 \sqrt {a}+1\right ) \operatorname {BesselI}\left (2 \sqrt {a},2 \sqrt {x}\right )\right \}\right \}\] ✓ Maple : cpu = 0.013 (sec), leaf count = 31
dsolve(x^2*diff(diff(y(x),x),x)+x*diff(y(x),x)-(x+a)*y(x)=0,y(x))
\[y \left (x \right ) = c_{1} \operatorname {BesselI}\left (2 \sqrt {a}, 2 \sqrt {x}\right )+c_{2} \operatorname {BesselK}\left (2 \sqrt {a}, 2 \sqrt {x}\right )\]