M000000013

$$\pi=152\arctan\left(\frac{1}{47}\right)-28\arctan\left(\frac{1}{305}\right)-24\arctan\left(\frac{2}{296489}\right)+28\arctan\left(\frac{1}{9916207}\right)-24\arctan\left(\frac{1}{18677233307}\right)-28\arctan\left(\frac{1}{1038377072894143}\right)$$