Machin-like formulae
M000305
$$\pi=48\arctan\left(\frac{1}{15}\right)-4\arctan\left(\frac{1}{239}\right)-16\arctan\left(\frac{1}{580}\right)-16\arctan\left(\frac{1}{1710}\right)$$
Compact formula
48[15] - 4[239] - 16[580] - 16[1710]
Lehmer's measure
1.94190
References
CASTELLANOS (1988)
(full reference coming soon)