OFFSET
0,1
REFERENCES
Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 6.3 Kepler-Bouwkamp constant, p. 428.
FORMULA
exp( -sum_{k >= 1} zeta(2*k)*(zeta(2*k)-1)/k ).
EXAMPLE
0.32870969168566393036259767023839643402099763855589812883...
MATHEMATICA
digits = 102; Exp[-NSum[Zeta[2*k]*(Zeta[2*k]-1)/k, {k, 1, Infinity}, NSumTerms -> 200, WorkingPrecision -> digits+10]] // RealDigits[#, 10, digits]& // First
CROSSREFS
KEYWORD
AUTHOR
Jean-François Alcover, Aug 01 2014
STATUS
approved