M000000166

$$\pi=\frac{5380}{7}\arctan\left(\frac{1}{239}\right)\frac{-3056}{7}\arctan\left(\frac{1}{5832}\right)\frac{-256}{7}\arctan\left(\frac{1}{103862}\right)+\frac{848}{7}\arctan\left(\frac{1}{110443}\right)\frac{-128}{7}\arctan\left(\frac{1}{740943}\right)+\frac{512}{7}\arctan\left(\frac{2}{2513489}\right)\frac{-848}{7}\arctan\left(\frac{1}{4841182}\right)\frac{-3056}{7}\arctan\left(\frac{1}{6826318}\right)$$