Machin-like formulae
M000402
$$\pi=16\arctan\left(\frac{1}{5}\right)+4\arctan\left(\frac{1}{41}\right)-8\arctan\left(\frac{1}{70}\right)$$
Compact formula
16[5] + 4[41] - 8[70]
Lehmer's measure
2.59269
References
STØRMER (1896)
(full reference coming soon)