Iν⁡(z)∼ⅇz(2⁢π⁢z)12⁢∑k=0∞(-1)k⁢ak⁡(ν)zk±ⅈ⁢ⅇ±ν⁢π⁢ⅈ⁢ⅇ-z(2⁢π⁢z)12⁢∑k=0∞ak⁡(ν)zk,