M000221

$$\pi=152\arctan\left(\frac{1}{47}\right)+28\arctan\left(\frac{1}{239}\right)-56\arctan\left(\frac{1}{268}\right)-48\arctan\left(\frac{1}{247057}\right)+24\arctan\left(\frac{1}{740943}\right)$$
Compact formula152[47] + 28[239] - 56[268] - 48[247057] + 24[740943]
Lehmer's measure1.78613
References
ASN (***) (full reference coming soon)