Machin-like formulae
M000397
$$\pi=14\arctan\left(\frac{2}{11}\right)+12\arctan\left(\frac{2}{39}\right)+6\arctan\left(\frac{1}{682}\right)$$
Compact formula
14[11/2] + 12[39/2] + 6[682]
Lehmer's measure
2.47874
References
MRW (***)
(full reference coming soon)