OFFSET
0,1
REFERENCES
Henri Cohen, Number Theory, Vol II: Analytic and Modern Tools, Springer (Graduate Texts in Mathematics 240), 2007.
LINKS
Karim Belabas, Henri Cohen, Computation of the Hardy-Littlewood constant for quadratic polynomials, PARI/GP script, 2020.
Henri Cohen, High-precision computation of Hardy-Littlewood constants, (1998). [pdf copy, with permission]
Keith Conrad, Hardy-Littlewood Constants, (2003).
FORMULA
C = (1/2)*Product_{p=primes} (1 - Kronecker(-4,p)/(p - 1))
EXAMPLE
0.686406731409123004556096348363509434089166550627879778968117...
PROG
(PARI) See Belabas, Cohen link. Run as HardyLittlewood2(x^2+1)/2 after setting the required precision.
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Hugo Pfoertner, Feb 02 2020
STATUS
approved