M000000226

$$\pi=64\arctan\left(\frac{1}{21}\right)+12\arctan\left(\frac{1}{239}\right)+16\arctan\left(\frac{1}{343}\right)-16\arctan\left(\frac{1}{27493}\right)$$

Compact formula	`64[21] + 12[239] + 16[343] - 16[27493]`
Lehmer's measure	1.79645
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 Matsumoto in 1996.] Download references as BibTeΧ