ψ⁡(pq)=-γ-ln⁡q-π2⁢cot⁡(π⁢pq)+12⁢∑k=1q-1cos⁡(2⁢π⁢k⁢pq)⁢ln⁡(2-2⁢cos⁡(2⁢π⁢kq)).