mml=<math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mrow><mfenced separators="|"><mrow><msub><mn>2</mn><mi mathvariant="normal">n</mi></msub><mo>+</mo><mn>1</mn></mrow></mfenced><mo>!</mo></mrow><mrow><mi mathvariant="normal">n</mi><mo>!</mo><mfenced separators="|"><mrow><mi mathvariant="normal">n</mi><mo>+</mo><mn>1</mn></mrow></mfenced><mo>!</mo></mrow></mfrac></math>