OFFSET
1,1
COMMENTS
For general definition of constants Pi(q,a) see Alessandro Languasco and Alessandro Zaccagnini 2010 p. 19 eq (4), for this particular case see p. 25.
LINKS
Alessandro Languasco and Alessandro Zaccagnini, On the constant in the Mertens product for arithmetic progressions. I. Identities, Funct. Approx. Comment. Math. Volume 42, Number 1 (2010), 17-27.
For more links see A340711.
FORMULA
Equals 25*sqrt(5)/(4*Pi^2*log((1+sqrt(5))/2)).
EXAMPLE
2.942584772269271492842068894927865...
MATHEMATICA
RealDigits[25 Sqrt[5]/(4 Pi^2 Log[1/2 (1 + Sqrt[5])]), 10, 105] // First
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Artur Jasinski, Jan 27 2021
EXTENSIONS
Name corrected by Alessandro Languasco, Feb 18 2021
STATUS
approved