M000003549

$$\pi=4\arctan\left(\frac{1}{2}\right)+8\arctan\left(\frac{1}{5}\right)-4\arctan\left(\frac{1}{17}\right)+8\arctan\left(\frac{1}{21}\right)-8\arctan\left(\frac{1}{32}\right)-8\arctan\left(\frac{1}{60}\right)-4\arctan\left(\frac{1}{70}\right)+8\arctan\left(\frac{1}{3107}\right)$$