The factor on the right is Hardy–Littlewood's twin prime constant Π 2 = ∏ p > 2 ( 1 − 1 ( p − 1 ) 2 ) = 0.6601618... {\displaystyle \Pi _{2}=\prod _{p>2}\left(1-{\frac {1}{(p-1)^{2}}}\right)=0.6601618...} Here the product is taken over all primes greater than 2. Le facteur sur la droite est la constante de premiers jumeaux Π 2 = ∏ p > 2 ( 1 − 1 ( p − 1 ) 2 ) = 0.6601618...
