Machin-like formulae
M000000495
$$\pi=16\arctan\left(\frac{1}{4}\right)-16\arctan\left(\frac{1}{21}\right)-4\arctan\left(\frac{1}{226}\right)+4\arctan\left(\frac{1}{4155}\right)$$
Compact formula
16[4] - 16[21] - 4[226] + 4[4155]
Lehmer's measure
3.11840