mml=<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>=</mo><mfrac><mrow><mfrac><mn>1</mn><mn>6</mn></mfrac><mi mathvariant="normal">n</mi><mfenced separators="|"><mrow><mi mathvariant="normal">n</mi><mo>+</mo><mn>1</mn></mrow></mfenced><mo>(</mo><mn>2</mn><mi mathvariant="normal">n</mi><mo>+</mo><mn>1</mn><mo>)</mo></mrow><mi mathvariant="normal">n</mi></mfrac><mspace linebreak="newline"/><mo>=</mo><mfrac><mn>1</mn><mn>6</mn></mfrac><mi mathvariant="normal">n</mi><mfenced separators="|"><mrow><mi mathvariant="normal">n</mi><mo>+</mo><mn>1</mn></mrow></mfenced><mo>(</mo><mn>2</mn><mi mathvariant="normal">n</mi><mo>+</mo><mn>1</mn><mo>)</mo></math>