Machin-like formulae
M000351
$$\pi=28\arctan\left(\frac{1}{11}\right)+12\arctan\left(\frac{2}{39}\right)-8\arctan\left(\frac{1}{682}\right)$$
Compact formula
28[11] + 12[39/2] - 8[682]
Lehmer's measure
2.08831
References
MRW (16Aug06)(*2.47875)
(full reference coming soon)