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A243371 Decimal expansion of 6*K/Pi^2, a constant related to the asymptotic evaluation of the number of positive squarefree integers of the form a^2 + b^2, where K is the Landau-Ramanujan constant. 0
4, 6, 4, 5, 9, 2, 2, 7, 0, 8, 9, 4, 7, 9, 0, 5, 1, 2, 9, 2, 0, 7, 6, 7, 4, 9, 3, 2, 0, 0, 8, 3, 6, 9, 1, 9, 4, 8, 0, 0, 4, 9, 3, 7, 0, 4, 2, 7, 9, 8, 6, 9, 5, 2, 2, 9, 8, 6, 0, 3, 1, 1, 1, 6, 1, 5, 2, 4, 1, 7, 7, 9, 6, 2, 6, 7, 2, 9, 2, 7, 4, 1, 9, 3, 3, 1, 7, 2, 1, 0, 8, 2, 0, 5, 6, 7, 8, 4, 1 (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..98.

Eric Weisstein's MathWorld, Ramanujan constant

FORMULA

6*K/Pi^2, where K is the Landau-Ramanujan constant.

EXAMPLE

0.46459227089479051292076749320083691948...

MATHEMATICA

digits = 99; 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]; 6*LandauRamanujanK/Pi^2 // RealDigits[#, 10, digits]& // First (* updated Mar 14 2018 *)

CROSSREFS

Cf. A064533.

Sequence in context: A137429 A132024 A092039 * A123999 A014110 A266491

Adjacent sequences:  A243368 A243369 A243370 * A243372 A243373 A243374

KEYWORD

nonn,cons

AUTHOR

Jean-Fran├žois Alcover, Jun 04 2014

STATUS

approved

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Last modified September 29 12:57 EDT 2022. Contains 357090 sequences. (Running on oeis4.)