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A065488 Decimal expansion of product(1 + 1/(p^2-p-1)), p prime >= 2). 0
2, 6, 7, 4, 1, 1, 2, 7, 2, 5, 5, 7, 0, 0, 2, 1, 5, 0, 8, 9, 6, 0, 4, 1, 1, 8, 3, 0, 4, 4, 5, 4, 8, 8, 0, 3, 7, 5, 0, 2, 3, 9, 8, 6, 2, 8, 3, 9, 7, 6, 9, 1, 9, 8, 5, 2, 0, 0, 8, 1, 9, 0, 4, 1, 9, 6, 0, 8, 6, 5, 9, 5, 6, 1, 0, 5, 3, 0, 2, 8, 6, 8, 6, 4, 4, 8, 5, 0, 9, 2, 9, 7, 1, 7, 3, 4, 8, 5, 7 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

This is 1/Artin's constant, see A005596.

LINKS

Table of n, a(n) for n=1..99.

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

EXAMPLE

2.67411272557002150896041183...

MATHEMATICA

$MaxExtraPrecision = 1200; digits = 99; terms = 1200; P[n_] := PrimeZetaP[n ]; LR = Join[{0, 0}, LinearRecurrence[{2, 0, -1}, {2, 3, 6}, term+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. A005596, A048296.

Sequence in context: A021378 A201891 A198430 * A016591 A021793 A327558

Adjacent sequences:  A065485 A065486 A065487 * A065489 A065490 A065491

KEYWORD

cons,nonn

AUTHOR

N. J. A. Sloane, Nov 19 2001

STATUS

approved

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Last modified October 17 10:07 EDT 2019. Contains 328108 sequences. (Running on oeis4.)