login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Please make a donation to keep the OEIS running. In 2018 we replaced the server with a faster one, added 20000 new sequences, and reached 7000 citations (often saying "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A065474 Decimal expansion of Feller-Tornier constant: Product_{p prime} (1 - 2/p^2). 14
3, 2, 2, 6, 3, 4, 0, 9, 8, 9, 3, 9, 2, 4, 4, 6, 7, 0, 5, 7, 9, 5, 3, 1, 6, 9, 2, 5, 4, 8, 2, 3, 7, 0, 6, 6, 5, 7, 0, 9, 5, 0, 5, 7, 9, 6, 6, 5, 8, 3, 2, 7, 0, 9, 9, 6, 1, 8, 1, 1, 2, 5, 2, 4, 5, 3, 2, 5, 0, 0, 6, 3, 4, 8, 6, 2, 4, 4, 6, 0, 9, 8, 8, 4, 5, 2, 3, 4, 8, 1, 5, 6, 8, 5, 6, 3, 7, 5 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Density of A007674, squarefree n such that n + 1 is squarefree. - Charles R Greathouse IV, Aug 10 2011

LINKS

Table of n, a(n) for n=0..97.

H. Cohen, High precision computation of Hardy-Littlewood constants.

R. J. Mathar, Hardy-Littlewood constants embedded into infinite products over all positive integers, arXiv:0903.2514 [math.NT], 2009-2011, constant F_1^(2).

G. Niklasch, Some number theoretical constants: 1000-digit values [Cached copy]

Eric Weisstein's World of Mathematics, Squarefree

Eric Weisstein's World of Mathematics, Prime Products

Zack Wolske, Number Fields with Large Minimal Index, Ph.D. Thesis, University of Toronto, 2018.

EXAMPLE

0.322634098939244670579531692548...

MATHEMATICA

$MaxExtraPrecision = 800; digits = 98; terms = 800; P[n_] := PrimeZetaP[n]; LR = Join[{0, 0}, LinearRecurrence[{0, 2}, {-4, 0}, terms + 10]]; r[n_Integer] := LR[[n]]; Exp[NSum[r[n]*P[n - 1]/(n - 1), {n, 3, terms}, NSumTerms -> terms, WorkingPrecision -> digits + 10]] // RealDigits[#, 10, digits]& // First (* Jean-Fran├žois Alcover, Apr 18 2016 *)

CROSSREFS

Cf. A007674, A065493, A074893.

Sequence in context: A285733 A106335 A218698 * A272332 A197586 A111702

Adjacent sequences:  A065471 A065472 A065473 * A065475 A065476 A065477

KEYWORD

cons,nonn

AUTHOR

N. J. A. Sloane, Nov 19 2001

EXTENSIONS

Edited by Dean Hickerson, Sep 10 2002

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 18 08:16 EST 2018. Contains 318219 sequences. (Running on oeis4.)