Machin-like formulae
M000374
$$\pi=16\arctan\left(\frac{1}{5}\right)-4\arctan\left(\frac{1}{213}\right)+4\arctan\left(\frac{1}{1958}\right)$$
Compact formula
16[5] - 4[213] + 4[1958]
Lehmer's measure
2.16394
References
STØRMER (1896)
(full reference coming soon)