Machin-like formulae
M000000500
$$\pi=16\arctan\left(\frac{1}{4}\right)-16\arctan\left(\frac{1}{21}\right)-4\arctan\left(\frac{1}{41}\right)+8\arctan\left(\frac{1}{99}\right)$$
Compact formula
16[4] - 16[21] - 4[41] + 8[99]
Lehmer's measure
3.53840