\[ \boxed { {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) -{\frac {\rm d}{{\rm d}x}}y \left ( x \right ) +{{\rm e}^{2\,x}}y \left ( x \right ) =0} \]
Mathematica: cpu = 0.011001 (sec), leaf count = 20 \[ \left \{\left \{y(x)\to c_2 \sin \left (e^x\right )+c_1 \cos \left (e^x\right )\right \}\right \} \]
Maple: cpu = 0.015 (sec), leaf count = 15 \[ \left \{ y \left ( x \right ) ={\it \_C1}\,\sin \left ( {{\rm e}^{x}} \right ) +{\it \_C2}\,\cos \left ( {{\rm e}^{x}} \right ) \right \} \]