M000000315

$$\pi=256\arctan\left(\frac{1}{80}\right)-4\arctan\left(\frac{1}{239}\right)-16\arctan\left(\frac{1}{515}\right)-32\arctan\left(\frac{1}{4030}\right)-64\arctan\left(\frac{1}{32060}\right)-128\arctan\left(\frac{1}{256120}\right)$$

Compact formula	`256[80] - 4[239] - 16[515] - 32[4030] - 64[32060] - 128[256120]`
Lehmer's measure	1.99886
References	Cashmore, M. Response to "Série la plus rapidement converfente pour le calcul du number π" (Brogard, H.), L'intermédiaire des mathematicians 26, 22–22, 1919. Download references as BibTeΧ