M000000459

$$\pi=\frac{32}{5}\arctan\left(\frac{1}{2}\right)+\frac{16}{5}\arctan\left(\frac{1}{18}\right)\frac{-4}{5}\arctan\left(\frac{1}{239}\right)$$

Compact formula	`32/5[2] + 16/5[18] - 4/5[239]`
Lehmer's measure	4.53901
References	Størmer, Carl. Solution complète en nombres entiers m, n, x, y et k de l'équation marctang(1/x) + narctang(1/y) = kπ/4, chapter 11 in Skrifter udgivne af Vidensakbsselskabet i Christiania I. Mathematisk-naturvidenskabelig klasse, 11.1–11.21, 1896. Download references as BibTeΧ