Machin-like formulae
M000391
$$\pi=16\arctan\left(\frac{1}{6}\right)+16\arctan\left(\frac{1}{31}\right)-4\arctan\left(\frac{1}{239}\right)$$
Compact formula
16[6] + 16[31] - 4[239]
Lehmer's measure
2.37607
References
STØRMER (1896)
(full reference coming soon)