cp's OEIS Frontend

The Hafner-Sarnak-McCurley constant. [Named after the American mathematician James Lee Hafner (1954-2015), the South-African and American mathematician Peter Clive Sarnak (b. 1953) and the American mathematician and computer scientist Kevin Snow McCurley. - Amiram Eldar, Jun 15 2021]

Comment on numerics from R. J. Mathar, Apr 20 2011: (Start)

The definition s = Product_{p} (1-[1- Product_{n>=1} (1-1/p^n)]^2) may be binomially expanded to s = Product_{p} Sum_{n>=1} (2*A010815(n)-A002107(n))/p^n. The auxiliary sequence 2*A010815(n)-A002107(n) is 1, 0, -1, -2, -1, 0, 2, 2, 2, 2, -1, 0,... for n>=0.

The inverse Euler transformation of the auxiliary sequence generates Sum_{n} (2*A010815(n)-A002107(n)) /p^n = Product_{n} (1-1/p^n)^gamma(n) with gamma(n) = 0, -1, -2 ,-1, -2, 0, -2, -1, 0, -2, 0, -1,... for n>=1. This yields s = Product_{n>=1} zeta(n)^gamma(n) where zeta(n) are the values of the Riemann zeta function.

(End)