Twin prime constant
From specialfunctionswiki
The twin prime constant is defined as $$C_2=\displaystyle\prod_{p \mathrm{\hspace{2pt} prime},p \geq 3} 1 - \dfrac{1}{(p-1)^2}.$$
The twin prime constant is defined as $$C_2=\displaystyle\prod_{p \mathrm{\hspace{2pt} prime},p \geq 3} 1 - \dfrac{1}{(p-1)^2}.$$
