M000001162

$$\pi=-8\arctan\left(\frac{1}{2}\right)+16\arctan\left(\frac{1}{5}\right)+12\arctan\left(\frac{1}{7}\right)+16\arctan\left(\frac{1}{13}\right)+16\arctan\left(\frac{1}{21}\right)$$

Compact formula	`- 8[2] + 16[5] + 12[7] + 16[13] + 16[21]`
Lehmer's measure	7.58991