\[ \boxed { \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) ^{2}- \left ( 4\,y \left ( x \right ) +1 \right ) {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) + \left ( 4\,y \left ( x \right ) +1 \right ) y \left ( x \right ) =0} \]
Mathematica: cpu = 0.074009 (sec), leaf count = 109 \[ \left \{\left \{y(x)\to -\frac {1}{4} e^{x-4 c_1} \left (2 e^{2 c_1}-e^x\right )\right \},\left \{y(x)\to \frac {1}{4} \left (\sinh \left (2 c_1+x\right )+\cosh \left (2 c_1+x\right )-2\right ) \left (\sinh \left (2 c_1+x\right )+\cosh \left (2 c_1+x\right )\right )\right \},\left \{y(x)\to \frac {1}{4} \left (\sinh \left (2 c_1+x\right )+\cosh \left (2 c_1+x\right )\right ) \left (\sinh \left (2 c_1+x\right )+\cosh \left (2 c_1+x\right )+2\right )\right \}\right \} \]
Maple: cpu = 0.811 (sec), leaf count = 193 \[ \left \{ y \left ( x \right ) =-{\frac {1}{4}},y \left ( x \right ) =-{ \frac { \left ( {{\rm e}^{x}} \right ) ^{2}}{2\,{\it \_C1}} \left ( -{ \frac {{\it \_C1}}{ \left ( {{\rm e}^{x}} \right ) ^{2}} \left ( \sqrt {- {\frac {{\it \_C1}}{ \left ( {{\rm e}^{x}} \right ) ^{2}}}}-2 \right ) { \frac {1}{\sqrt {-{\frac {{\it \_C1}}{ \left ( {{\rm e}^{x}} \right ) ^{ 2}}}}}}}+{\frac {{\it \_C1}}{ \left ( {{\rm e}^{x}} \right ) ^{2}}}+2 \right ) },y \left ( x \right ) ={\frac { \left ( {{\rm e}^{x}} \right ) ^ {2}}{2\,{\it \_C1}} \left ( {\frac {{\it \_C1}}{ \left ( {{\rm e}^{x}} \right ) ^{2}} \left ( \sqrt {-{\frac {{\it \_C1}}{ \left ( {{\rm e}^{x} } \right ) ^{2}}}}-2 \right ) {\frac {1}{\sqrt {-{\frac {{\it \_C1}}{ \left ( {{\rm e}^{x}} \right ) ^{2}}}}}}}-{\frac {{\it \_C1}}{ \left ( { {\rm e}^{x}} \right ) ^{2}}}-2 \right ) },y \left ( x \right ) =-{\frac { \left ( {{\rm e}^{x}} \right ) ^{2}}{2\,{\it \_C1}} \left ( -{\frac {{ \it \_C1}}{ \left ( {{\rm e}^{x}} \right ) ^{2}} \left ( \sqrt {-{\frac { {\it \_C1}}{ \left ( {{\rm e}^{x}} \right ) ^{2}}}}+2 \right ) {\frac {1} {\sqrt {-{\frac {{\it \_C1}}{ \left ( {{\rm e}^{x}} \right ) ^{2}}}}}}}+ {\frac {{\it \_C1}}{ \left ( {{\rm e}^{x}} \right ) ^{2}}}+2 \right ) },y \left ( x \right ) ={\frac { \left ( {{\rm e}^{x}} \right ) ^{2}}{2\,{ \it \_C1}} \left ( {\frac {{\it \_C1}}{ \left ( {{\rm e}^{x}} \right ) ^{ 2}} \left ( \sqrt {-{\frac {{\it \_C1}}{ \left ( {{\rm e}^{x}} \right ) ^ {2}}}}+2 \right ) {\frac {1}{\sqrt {-{\frac {{\it \_C1}}{ \left ( { {\rm e}^{x}} \right ) ^{2}}}}}}}-{\frac {{\it \_C1}}{ \left ( {{\rm e}^{ x}} \right ) ^{2}}}-2 \right ) } \right \} \]