Machin-like formulae
M000282
$$\pi=68\arctan\left(\frac{1}{26}\right)+20\arctan\left(\frac{1}{38}\right)+12\arctan\left(\frac{1}{2057}\right)-40\arctan\left(\frac{1}{8827}\right)$$
Compact formula
68[26] + 20[38] + 12[2057] - 40[8827]
Lehmer's measure
1.89497
References
ARNDT (1993)
(full reference coming soon)