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.

A361062 Decimal expansion of the asymptotic mean of A073184(k)/A000005(k), the ratio between the number of cubefree divisors and the number of divisors.

Original entry on oeis.org

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

Views

Author

Amiram Eldar, Mar 01 2023

Keywords

Examples

			0.939974352176477078470442562386025726769842310977996...
		

Crossrefs

Cf. A000005, A073184, A361061 (mean of the inverse ratio).
Cf. A307869, A308043 (squarefree analog).

Programs

  • Mathematica
    $MaxExtraPrecision = 1000; m = 1000; f[p_] := -(p-1)*(1+4*p+6*p^2*Log[1-1/p])/(2*p^2); c = Rest[CoefficientList[Series[Log[f[1/x]], {x, 0, m}], x]]; RealDigits[Exp[NSum[Indexed[c, n]*(PrimeZetaP[n]), {n, 2, m}, NSumTerms -> m, WorkingPrecision -> m]], 10, 100][[1]]

Formula

Equals lim_{m->oo} (1/m) * Sum_{k=1..m} A073184(k)/A000005(k).
Equals Product_{p prime} (-(p-1)*(1+4*p+6*p^2*log(1-1/p))/(2*p^2)).