OFFSET
1,3
FORMULA
Product_p Sum_{k>=0} 1/sigma_3(p^k).
EXAMPLE
1.183473506178851103857342368295209694536571021407175977168478853541741442...
MATHEMATICA
$MaxExtraPrecision = 1000; Do[Clear[f]; f[p_] := (1 + Sum[(p^3 - 1)/(p^(3 e + 3) - 1), {e, 1, emax}]); m = 1000; cc = Rest[CoefficientList[Series[Log[f[1/x]], {x, 0, m+3}], x]]; Print[f[2]*Exp[N[Sum[Indexed[cc, n]*(PrimeZetaP[n] - 1/2^n), {n, 2, m}], 120]]], {emax, 100, 400, 100}]
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Vaclav Kotesovec, Sep 19 2020
STATUS
approved