Machin-like formulae
M000000518
$$\pi=12\arctan\left(\frac{1}{5}\right)+4\arctan\left(\frac{1}{20}\right)+12\arctan\left(\frac{1}{21}\right)+4\arctan\left(\frac{1}{1985}\right)$$
Compact formula
12[5] + 4[20] + 12[21] + 4[1985]
Lehmer's measure
3.25883