M000003590

$$\pi=12\arctan\left(\frac{1}{5}\right)-8\arctan\left(\frac{1}{9}\right)+12\arctan\left(\frac{1}{16}\right)+12\arctan\left(\frac{1}{21}\right)+8\arctan\left(\frac{1}{50}\right)+12\arctan\left(\frac{1}{64}\right)+4\arctan\left(\frac{1}{682}\right)-12\arctan\left(\frac{1}{787}\right)$$