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A245781 Decimal expansion of the infinite product of (j/Pi)*sin(Pi/j), for j >= 2, a constant similar to the Kepler-Bouwkamp constant. 0
3, 2, 8, 7, 0, 9, 6, 9, 1, 6, 8, 5, 6, 6, 3, 9, 3, 0, 3, 6, 2, 5, 9, 7, 6, 7, 0, 2, 3, 8, 3, 9, 6, 4, 3, 4, 0, 2, 0, 9, 9, 7, 6, 3, 8, 5, 5, 5, 8, 9, 8, 1, 2, 8, 8, 3, 0, 0, 3, 1, 8, 5, 4, 3, 5, 4, 7, 2, 1, 3, 5, 2, 6, 8, 4, 4, 0, 5, 9, 9, 7, 8, 9, 5, 5, 5, 3, 9, 0, 6, 2, 5, 7, 6, 7, 9, 9, 5, 6, 4, 4, 7 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

REFERENCES

Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 6.3 Kepler-Bouwkamp constant, p. 428.

LINKS

Table of n, a(n) for n=0..101.

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

Cf. A085365.

Sequence in context: A117822 A132887 A092174 * A239803 A083514 A123696

Adjacent sequences:  A245778 A245779 A245780 * A245782 A245783 A245784

KEYWORD

nonn,cons,easy

AUTHOR

Jean-Fran├žois Alcover, Aug 01 2014

STATUS

approved

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Last modified February 17 17:12 EST 2019. Contains 320222 sequences. (Running on oeis4.)