M000000309

$$\pi=48\arctan\left(\frac{1}{18}\right)+32\arctan\left(\frac{1}{75}\right)+12\arctan\left(\frac{1}{239}\right)+32\arctan\left(\frac{1}{39307}\right)$$

Compact formula	`48[18] + 32[75] + 12[239] + 32[39307]`
Lehmer's measure	1.96805
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 26 January 1995.] Download references as BibTeΧ