M000003574

$$\pi=8\arctan\left(\frac{1}{5}\right)+4\arctan\left(\frac{1}{11}\right)+8\arctan\left(\frac{1}{15}\right)+8\arctan\left(\frac{1}{21}\right)+4\arctan\left(\frac{1}{32}\right)+4\arctan\left(\frac{1}{50}\right)+8\arctan\left(\frac{1}{81}\right)-8\arctan\left(\frac{1}{467}\right)$$