M000000127

$$\pi=\frac{166}{7}\arctan\left(\frac{2}{15}\right)\frac{-22}{7}\arctan\left(\frac{1}{1710}\right)+\frac{48}{7}\arctan\left(\frac{1}{105218}\right)\frac{-4}{7}\arctan\left(\frac{2}{2513489}\right)+\frac{48}{7}\arctan\left(\frac{1}{7167807}\right)$$