<math xmlns='http://www.w3.org/1998/Math/MathML'><semantics><mrow xref='id23'><mrow xref='id21'><mrow xref='id9'><mrow><mrow><mn xref='id1'>2</mn><mo>⁢</mo><mrow xref='id4'><mi xref='id2'>u</mi><mo>⁡</mo><mfenced><mi xref='id3'>n</mi></mfenced></mrow></mrow><mo>⁢</mo><mfenced><mrow xref='id7'><mi xref='id5'>n</mi><mo>+</mo><mfrac xref='id6'><mn>1</mn><mn>2</mn></mfrac></mrow></mfenced></mrow><mo>⁢</mo><mi xref='id8'>n</mi></mrow><mo>+</mo><mrow xref='id20'><mrow xref='id14'><mi xref='id10'>u</mi><mo>⁡</mo><mfenced><mrow xref='id13'><mi xref='id11'>n</mi><mo>-</mo><mn xref='id12'>1</mn></mrow></mfenced></mrow><mo>⁢</mo><mrow xref='id19'><msup><mfenced><mrow xref='id17'><mfrac xref='id15'><mn>-1</mn><mn>2</mn></mfrac><mo>+</mo><mi xref='id16'>n</mi></mrow></mfenced><mn xref='id18'>2</mn></msup></mrow></mrow></mrow><mo>=</mo><mn xref='id22'>0</mn></mrow><annotation-xml encoding='MathML-Content'><apply id='id23'><eq/><apply id='id21'><plus/><apply id='id9'><times/><cn id='id1' type='integer'>2</cn><apply id='id4'><ci id='id2'>u</ci><ci id='id3'>n</ci></apply><apply id='id7'><plus/><ci id='id5'>n</ci><cn id='id6' type='rational'>1<sep/>2</cn></apply><ci id='id8'>n</ci></apply><apply id='id20'><times/><apply id='id14'><ci id='id10'>u</ci><apply id='id13'><minus/><ci id='id11'>n</ci><cn id='id12' type='integer'>1</cn></apply></apply><apply id='id19'><power/><apply id='id17'><plus/><cn id='id15' type='rational'>-1<sep/>2</cn><ci id='id16'>n</ci></apply><cn id='id18' type='integer'>2</cn></apply></apply></apply><cn id='id22' type='integer'>0</cn></apply></annotation-xml><annotation encoding='Maple'>2*u(n)*(n+1/2)*n+u(n-1)*(-1/2+n)^2 = 0</annotation></semantics></math>