M000003561

$$\pi=4\arctan\left(\frac{1}{2}\right)+12\arctan\left(\frac{1}{3}\right)-8\arctan\left(\frac{1}{5}\right)+4\arctan\left(\frac{1}{13}\right)-12\arctan\left(\frac{1}{15}\right)-8\arctan\left(\frac{1}{21}\right)-12\arctan\left(\frac{1}{81}\right)+12\arctan\left(\frac{1}{467}\right)$$

Compact formula	`4[2] + 12[3] - 8[5] + 4[13] - 12[15] - 8[21] - 12[81] + 12[467]`
Lehmer's measure	10.2514