\[ y''(x)-\left (2 e^x+1\right ) y'(x)+e^{2 x} y(x)-e^{3 x}=0 \] ✓ Mathematica : cpu = 0.0429803 (sec), leaf count = 28
DSolve[-E^(3*x) + E^(2*x)*y[x] - (1 + 2*E^x)*Derivative[1][y][x] + Derivative[2][y][x] == 0,y[x],x]
\[\left \{\left \{y(x)\to e^x+c_1 e^{e^x}+c_2 e^{x+e^x}+2\right \}\right \}\] ✓ Maple : cpu = 0.291 (sec), leaf count = 34
dsolve(diff(diff(y(x),x),x)-(2*exp(x)+1)*diff(y(x),x)+exp(2*x)*y(x)-exp(3*x)=0,y(x))
\[y \left (x \right ) = {\mathrm e}^{{\mathrm e}^{x}+\frac {x}{2}} \sinh \left (\frac {x}{2}\right ) c_{2}+{\mathrm e}^{{\mathrm e}^{x}+\frac {x}{2}} \cosh \left (\frac {x}{2}\right ) c_{1}+{\mathrm e}^{x}+2\]