Machin-like formulae
M000000503
$$\pi=16\arctan\left(\frac{1}{4}\right)-16\arctan\left(\frac{1}{21}\right)-4\arctan\left(\frac{1}{265}\right)-4\arctan\left(\frac{1}{2436}\right)$$
Compact formula
16[4] - 16[21] - 4[265] - 4[2436]
Lehmer's measure
3.12521