Machin-like formulae
M000414
$$\pi=10\arctan\left(\frac{1}{3}\right)-2\arctan\left(\frac{1}{26}\right)+2\arctan\left(\frac{1}{2057}\right)$$
Compact formula
10[3] - 2[26] + 2[2057]
Lehmer's measure
3.10445
References
STØRMER (1896)
(full reference coming soon)