Porter's constant
From specialfunctionswiki
Porter's constant $C$ is given by $$C=\dfrac{6\log(2)}{\pi^2} \left[ 3 \log(2)+4 \gamma - \dfrac{24}{\pi^2} \zeta'(2)-2 \right]-\dfrac{1}{2},$$ where $\log$ denotes the logarithm, $\pi$ denotes pi, $\gamma$ denotes the Euler-Mascheroni constant, and $\zeta$ denotes the Riemann zeta function.
