H1⁡(z)=2π⁢(1-J0⁡(z))+4π⁢∑k=1∞J2⁢k⁡(z)4⁢k2-1=4⁢∑k=0∞J2⁢k+12⁡(12⁢z)⁢J2⁢k+32⁡(12⁢z).