This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A088539 Decimal expansion of (4K/Pi)^2 where K is the Landau-Ramanujan constant. 1
 9, 4, 6, 8, 0, 6, 4, 0, 7, 1, 8, 0, 0, 7, 9, 3, 3, 4, 2, 1, 6, 0, 9, 4, 4, 1, 3, 1, 0, 9, 7, 5, 6, 2, 3, 3, 2, 5, 0, 0, 6, 9, 5, 0, 2, 6, 4, 7, 1, 6, 5, 3, 1, 2, 1, 8, 1, 9, 7, 9, 5, 6, 5, 5, 3, 5, 8, 2, 0, 1, 0, 6, 6, 3, 9, 3, 6, 3, 7, 9, 2, 8, 1, 3, 9, 8, 9, 1, 3, 3, 0, 0, 4, 9, 9, 6, 2, 6, 0, 5, 2, 3, 4, 3 (list; constant; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 REFERENCES S. R. Finch, Mathematical Constants, Encyclopedia of Mathematics and its Applications, vol. 94, Cambridge University Press, p. 100 LINKS W. Bosma and P. Stevenhagen, Density computations for real quadratic units, Math. comp. 65 (1996), 1327-1337; MR 96j : 11171. FORMULA Equals prod(1-1/p^2) where p runs through the primes p==1 mod 4 EXAMPLE 0.9468064071800793342160944131097562332500695... MATHEMATICA digits = 104; 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]; (4*LandauRamanujanK/Pi)^2 // RealDigits[#, 10, digits]& // First (* Jean-François Alcover, Mar 04 2013, updated Mar 14 2018 *) CROSSREFS Cf. A064533. Square of A244659. Sequence in context: A309610 A198989 A255013 * A245084 A199054 A131109 Adjacent sequences:  A088536 A088537 A088538 * A088540 A088541 A088542 KEYWORD cons,nonn AUTHOR Benoit Cloitre, Nov 16 2003 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 18 22:03 EDT 2019. Contains 328211 sequences. (Running on oeis4.)