M000376

$$\pi=40\arctan\left(\frac{1}{22}\right)+28\arctan\left(\frac{1}{41}\right)+48\arctan\left(\frac{1}{75}\right)+8\arctan\left(\frac{1}{4193}\right)$$
Compact formula40[22] + 28[41] + 48[75] + 8[4193]
Lehmer's measure2.17433
References
STØRMER (1896) (full reference coming soon)