cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A380601 Decimal expansion of the asymptotic mean of the ratio A322483(k)/A000005(k).

Original entry on oeis.org

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

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Author

Amiram Eldar, Jan 27 2025

Keywords

Examples

			0.85980677933034363311244767594941832466515809551385...
		

Crossrefs

Cf. A000005, A322483, A380602 (mean of the inverse ratio).
Similar constants: A308043, A361060, A361062.

Programs

  • Mathematica
    $MaxExtraPrecision = 1000; m = 1000; f[x_] := (2*x + 3*(x-1)*Log[1 - x] + (x-1)*Log[1+x])/(4*x); c = Rest[CoefficientList[Series[Log[f[x]], {x, 0, m}], x]]; RealDigits[Exp[NSum[Indexed[c, k]*PrimeZetaP[k], {k, 2, m}, NSumTerms -> m, WorkingPrecision -> m]], 10, 120][[1]]
  • PARI
    default(realprecision, 120); default(parisize, 30000000);
    my(m = 1024, x = 'x + O('x^m), v); v = Vec((2*x + 3*(x-1)*log(1-x) + (x-1)*log(1+x))/(4*x)); prodeulerrat(sum(i=1, #v, v[i]/p^(i-1)))

Formula

Equals lim_{m->oo} (1/m) * Sum_{k=1..m} A322483(k)/A000005(k).
Equals Product_{p prime} (1/2 - ((p-1)/4) * (3*log(1-1/p) + log(1+1/p))).
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