This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A065465 Decimal expansion of product(1 - 1/(p^2*(p+1))), p prime >= 2). 3
 8, 8, 1, 5, 1, 3, 8, 3, 9, 7, 2, 5, 1, 7, 0, 7, 7, 6, 9, 2, 8, 3, 9, 1, 8, 2, 2, 9, 0, 3, 2, 2, 7, 8, 4, 7, 1, 2, 9, 8, 6, 9, 2, 5, 7, 2, 0, 8, 0, 7, 6, 7, 3, 3, 6, 7, 0, 1, 6, 8, 5, 3, 5, 5, 4, 8, 6, 5, 7, 9, 0, 6, 3, 7, 9, 4, 1, 6, 9, 7, 4, 1, 0, 2, 2, 0, 4, 5, 5, 1, 7, 9, 7, 0, 2, 0, 9, 6 (list; constant; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS Eckford Cohen, Arithmetical functions associated with the unitary divisors of an integer, Math. Zeitschr. 74 (1960) 66-80. S. R. Finch, Class number theory, page 7. [Cached copy, with permission of the author] R. J. Mathar, Hardy-Littlewood constants embedded into infinite products..., arXiv:0903.2514 [math.NT], 2009-2011, Table 5, constant Q_1^(2). G. Niklasch, Some number theoretical constants: 1000-digit values [Cached copy] Simon Plouffe, Generalized expansions of real numbers, 2006 Eric Weisstein's World of Mathematics, Quadratic Class Number Constant Eric Weisstein's World of Mathematics, Prime Products FORMULA sum_{n>=1} phi(n)/(n*J(n)) = (this constant)*A013661 with phi()=A000010() and J() = A007434() [Cohen, Corollary 5.1.1], - R. J. Mathar, Apr 11 2011 EXAMPLE 0.88151383972517077692839182290... MATHEMATICA \$MaxExtraPrecision = 1000; digits = 98; terms = 1000; LR = Join[{0, 0, 0}, LinearRecurrence[{-2, -1, 1, 1}, {-3, 4, -5, 3}, terms+10]]; r[n_Integer] := LR[[n]]; Exp[NSum[r[n]*PrimeZetaP[n-1]/(n-1), {n, 4, terms}, NSumTerms -> terms, WorkingPrecision -> digits+10]] // RealDigits[#, 10, digits]& // First (* Jean-François Alcover, Apr 16 2016 *) CROSSREFS Cf. A078087. Sequence in context: A135707 A021923 A296496 * A265308 A319858 A199597 Adjacent sequences:  A065462 A065463 A065464 * A065466 A065467 A065468 KEYWORD cons,nonn AUTHOR N. J. A. Sloane, Nov 19 2001 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 December 14 07:03 EST 2019. Contains 329978 sequences. (Running on oeis4.)