Changes

<math>\pi = \sum_{i=0}^\infty \frac{1}{16^i} \left ( \frac{4}{8i+1} - \frac{2}{8i+4} - \frac{1}{8i+5} - \frac{1}{8i+6} \right )</math>

Hey, it doesn't work! Are there some modules that need to be installed or something?