A065470 Decimal expansion of Product_{p prime} (1 - 1/(p*(p^2-1))).

7, 8, 8, 1, 6, 2, 5, 0, 0, 0, 3, 0, 2, 2, 0, 7, 0, 0, 5, 7, 6, 9, 4, 9, 5, 9, 3, 0, 5, 3, 5, 0, 3, 9, 6, 8, 9, 5, 6, 1, 6, 3, 6, 8, 4, 6, 9, 3, 5, 6, 9, 3, 0, 3, 3, 5, 2, 5, 1, 4, 2, 9, 2, 1, 2, 7, 5, 4, 1, 3, 2, 9, 4, 1, 9, 7, 8, 5, 4, 6, 4, 0, 4, 2, 4, 8, 6, 5, 4, 4, 0, 6, 9, 8, 8, 1, 2, 3

Offset: 0

Author

N. J. A. Sloane, Nov 19 2001

Keywords

• cons
• nonn

Examples

			0.7881625000302207005769495930535...
		

Links

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

Crossrefs

Cf. A072801, A381481.

Programs

Mathematica

$MaxExtraPrecision = 600; digits = 98; terms = 600; P[n_] := PrimeZetaP[n];
LR = Join[{0, 0, 0}, LinearRecurrence[{0, 2, 1, -1, -1}, {-3, 0, -5, -3, -7}, 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-François Alcover, Apr 18 2016 *)

PARI

prodeulerrat(1 - 1/(p*(p^2-1))) \\ Amiram Eldar, Mar 13 2021