Machin-like formulae
M000071
$$\pi=636\arctan\left(\frac{1}{239}\right)+96\arctan\left(\frac{1}{268}\right)+304\arctan\left(\frac{1}{2478}\right)-48\arctan\left(\frac{1}{247057}\right)-128\arctan\left(\frac{1}{740943}\right)+304\arctan\left(\frac{1}{620658852}\right)$$
Compact formula
636[239] + 96[268] + 304[2478] - 48[247057] - 128[740943] + 304[620658852]
Lehmer's measure
1.59644
References
KOEPP (1994)(ΒΆΒΆ2.19252)
(full reference coming soon)