∫0zK0⁡(t)⁢ⅆ⁡t-2π⁢(ln⁡(2⁢z)+γ)∼2π⁢∑k=1∞(-1)k+1⁢(2⁢k)!⁢(2⁢k-1)!(k!)2⁢(2⁢z)2⁢k,