M000315

$$\pi=256\arctan\left(\frac{1}{80}\right)-4\arctan\left(\frac{1}{239}\right)-16\arctan\left(\frac{1}{515}\right)-32\arctan\left(\frac{1}{4030}\right)-64\arctan\left(\frac{1}{32060}\right)-128\arctan\left(\frac{1}{256120}\right)$$