Machin-like formulae
M000000494
$$\pi=16\arctan\left(\frac{1}{4}\right)-16\arctan\left(\frac{1}{21}\right)-8\arctan\left(\frac{1}{478}\right)+4\arctan\left(\frac{1}{54608393}\right)$$
Compact formula
16[4] - 16[21] - 8[478] + 4[54608393]
Lehmer's measure
2.91972