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A243376 Decimal expansion of 2*K/Pi, a constant related to the asymptotic evaluation of the number of positive integers all of whose prime factors are congruent to 3 modulo 4, where K is the Landau-Ramanujan constant. 0
4, 8, 6, 5, 1, 9, 8, 8, 8, 3, 8, 5, 8, 9, 0, 9, 9, 7, 1, 2, 7, 2, 4, 5, 6, 4, 0, 5, 8, 6, 8, 2, 3, 4, 0, 5, 5, 3, 8, 1, 7, 1, 9, 8, 1, 7, 3, 9, 5, 4, 1, 2, 1, 3, 6, 8, 8, 1, 5, 4, 5, 1, 0, 8, 1, 6, 2, 9, 8, 5, 5, 0, 9, 3, 2, 0, 7, 5, 8, 1, 7, 1, 4, 7, 6, 0, 2, 0, 2, 1, 0, 3, 8, 1, 0, 6, 9, 3, 7, 1, 2 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

REFERENCES

Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 2.3 Landau-Ramanujan constant, p. 100.

LINKS

Table of n, a(n) for n=0..100.

Eric Weisstein's MathWorld, Ramanujan constant

FORMULA

2*K/Pi, where K is the Landau-Ramanujan constant (A064533).

EXAMPLE

0.4865198883858909971272456405868234...

MATHEMATICA

digits = 101; LandauRamanujanK =  1/Sqrt[2]*NProduct[((1 - 2^(-2^n))*Zeta[2^n]/DirichletBeta[2^n])^(1/2^(n + 1)), {n, 1, 24}, WorkingPrecision -> digits + 5]; 2*LandauRamanujanK/Pi // RealDigits[#, 10, digits] & // First (* updated Mar 14 2018 *)

CROSSREFS

Cf. A064533.

Sequence in context: A296488 A199294 A155741 * A200411 A198885 A177157

Adjacent sequences:  A243373 A243374 A243375 * A243377 A243378 A243379

KEYWORD

nonn,cons

AUTHOR

Jean-Fran├žois Alcover, Jun 04 2014

STATUS

approved

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Last modified February 28 10:22 EST 2020. Contains 332323 sequences. (Running on oeis4.)