M000000176

$$\pi=176\arctan\left(\frac{1}{57}\right)+28\arctan\left(\frac{1}{239}\right)-96\arctan\left(\frac{1}{1432}\right)+48\arctan\left(\frac{1}{12238}\right)+96\arctan\left(\frac{1}{628103}\right)$$
Compact formula176[57] + 28[239] - 96[1432] + 48[12238] + 96[628103]
Lehmer's measure1.72393
References
Wetherfield, Michael Roby and Chien-Lih, Hwang. Computing pi: Lists of Machin-type (inverse cotangent) identities for pi/4, [Online; accessed 04-February-2024], 2013. [web.archive.org/web/20240204042153/http] [Found by HCL on 12 October 1997.]