M000000311

$$\pi=\frac{176}{5}\arctan\left(\frac{1}{11}\right)\frac{-36}{5}\arctan\left(\frac{1}{239}\right)\frac{-64}{5}\arctan\left(\frac{1}{682}\right)\frac{-48}{5}\arctan\left(\frac{1}{12943}\right)$$