Machin-like formulae
M000000512
$$\pi=16\arctan\left(\frac{1}{4}\right)-16\arctan\left(\frac{1}{21}\right)-4\arctan\left(\frac{1}{70}\right)+4\arctan\left(\frac{1}{99}\right)$$
Compact formula
16[4] - 16[21] - 4[70] + 4[99]
Lehmer's measure
3.46033