centerbaseline=false mml=<math xmlns="http://www.w3.org/1998/Math/MathML"><munderover><mo>∑</mo><mrow><mi mathvariant="normal">x</mi><mo>=</mo><mn>1</mn></mrow><mn>6</mn></munderover><mrow><msup><mn>2</mn><mi mathvariant="normal">x</mi></msup><mi mathvariant="normal">f</mi><mo>(</mo><mi mathvariant="normal">x</mi><mo>)</mo></mrow></math>