# Definition:Artin's Constant

 $\ds C_{\text {Artin} }$ $=$ $\ds \prod_{\text {p prime} } \paren {1 - \dfrac 1 {p^2 - p} }$ $\ds$ $=$ $\ds 0 \cdotp 37395 \, 58136 \, 19202 \, 28805 \ldots$