Bi′⁡(z⁢ⅇ±π⁢ⅈ/3)∼2π⁢ⅇ∓π⁢ⅈ/6⁢z1/4⁢(-sin⁡(ζ-14⁢π∓12⁢ⅈ⁢ln⁡2)⁢∑k=0∞(-1)k⁢v2⁢kζ2⁢k+cos⁡(ζ-14⁢π∓12⁢ⅈ⁢ln⁡2)⁢∑k=0∞(-1)k⁢v2⁢k+1ζ2⁢k+1),