<math xmlns='http://www.w3.org/1998/Math/MathML'><semantics><mrow xref='id24'><mrow xref='id22'><mrow xref='id7'><mrow xref='id3'><msup><mi xref='id1'>n</mi><mn xref='id2'>2</mn></msup></mrow><mo>⁢</mo><mrow xref='id6'><mi xref='id4'>u</mi><mo>⁡</mo><mfenced><mi xref='id5'>n</mi></mfenced></mrow></mrow><mo>+</mo><mrow xref='id21'><mfenced><mrow xref='id15'><mrow><mo>-</mo><mrow xref='id10'><msup><mi xref='id8'>n</mi><mn xref='id9'>2</mn></msup></mrow></mrow><mo>-</mo><mrow xref='id13'><mn xref='id11'>3</mn><mo>⁢</mo><mi xref='id12'>n</mi></mrow><mo>-</mo><mn xref='id14'>2</mn></mrow></mfenced><mo>⁢</mo><mrow xref='id20'><mi xref='id16'>u</mi><mo>⁡</mo><mfenced><mrow xref='id19'><mi xref='id17'>n</mi><mo>+</mo><mn xref='id18'>2</mn></mrow></mfenced></mrow></mrow></mrow><mo>=</mo><mn xref='id23'>0</mn></mrow><annotation-xml encoding='MathML-Content'><apply id='id24'><eq/><apply id='id22'><plus/><apply id='id7'><times/><apply id='id3'><power/><ci id='id1'>n</ci><cn id='id2' type='integer'>2</cn></apply><apply id='id6'><ci id='id4'>u</ci><ci id='id5'>n</ci></apply></apply><apply id='id21'><times/><apply id='id15'><plus/><apply><minus/><apply id='id10'><power/><ci id='id8'>n</ci><cn id='id9' type='integer'>2</cn></apply></apply><apply><minus/><apply id='id13'><times/><cn id='id11' type='integer'>3</cn><ci id='id12'>n</ci></apply></apply><cn id='id14' type='integer'>-2</cn></apply><apply id='id20'><ci id='id16'>u</ci><apply id='id19'><plus/><ci id='id17'>n</ci><cn id='id18' type='integer'>2</cn></apply></apply></apply></apply><cn id='id23' type='integer'>0</cn></apply></annotation-xml><annotation encoding='Maple'>n^2*u(n)+(-n^2-3*n-2)*u(n+2) = 0</annotation></semantics></math>