Way to show your ignorance, 3bodyproblem.
Equation 26 is "the globally averaged incident solar entropy flux received at the TOA for a blackbody Sun under the assumption II".
The entropy flux is defined as the
result of an integration over all all wavelengths. It is not a paramneter.
The integration is replaced by equation 16. So you could calcuate the temperature of the Sun or the distance to the Sun from the entropy flux

.
Try substituting the value of entry flux and calculating the energy flux, 3bodyproblem.