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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A383705 Numerator of Dirichlet g.f.: Sum_{n>=1} a(n)/n^s = zeta(s)^(2/3).

Original entry on oeis.org

1, 2, 2, 5, 2, 4, 2, 40, 5, 4, 2, 10, 2, 4, 4, 110, 2, 10, 2, 10, 4, 4, 2, 80, 5, 4, 40, 10, 2, 8, 2, 308, 4, 4, 4, 25, 2, 4, 4, 80, 2, 8, 2, 10, 10, 4, 2, 220, 5, 10, 4, 10, 2, 80, 4, 80, 4, 4, 2, 20, 2, 4, 10, 2618, 4, 8, 2, 10, 4, 8, 2, 200, 2, 4, 10, 10, 4
Offset: 1

Views

Author

Vaclav Kotesovec, May 06 2025

Keywords

Crossrefs

Cf. A256689 (denominator).

Programs

  • Mathematica
    coeff=CoefficientList[Series[1/(1-x)^(2/3),{x,0,20}]//Normal,x];dptTerm[n_]:=Module[{flist=FactorInteger[n]},If[n==1,coeff[[1]],Numerator[Times@@(coeff[[flist[[All,2]]+1]])]]];Array[dptTerm,77] (* Shenghui Yang, May 06 2025 *)
  • PARI
    for(n=1, 100, print1(numerator(direuler(p=2, n, 1/(1-X)^(2/3))[n]), ", "))

Formula

Sum_{k=1..n} a(k)/A256689(k) ~ n / (Gamma(2/3) * log(n)^(1/3)) * (1 + (1 - 2*gamma/3)/(3*log(n))), where gamma is the Euler-Mascheroni constant A001620 and Gamma() is the gamma function.

A383658 Denominator of Dirichlet g.f.: Sum_{n>=1} a(n)/n^s = zeta(s)^(3/2).

Original entry on oeis.org

1, 2, 2, 8, 2, 4, 2, 16, 8, 4, 2, 16, 2, 4, 4, 128, 2, 16, 2, 16, 4, 4, 2, 32, 8, 4, 16, 16, 2, 8, 2, 256, 4, 4, 4, 64, 2, 4, 4, 32, 2, 8, 2, 16, 16, 4, 2, 256, 8, 16, 4, 16, 2, 32, 4, 32, 4, 4, 2, 32, 2, 4, 16, 1024, 4, 8, 2, 16, 4, 8, 2, 128, 2, 4, 16, 16, 4
Offset: 1

Views

Author

Vaclav Kotesovec, May 04 2025

Keywords

Comments

Is this a duplicate of A046644 (the first 8192 entries are the same)? - R. J. Mathar, May 06 2025

Crossrefs

Programs

  • Mathematica
    coeff=CoefficientList[Series[1/(1-x)^(3/2),{x,0,20}]//Normal,x]; dptTerm[n_]:=Module[{flist=FactorInteger[n]},If[n==1,coeff[[1]],Denominator[Times@@(coeff[[flist[[All,2]]+1]])]]];Array[dptTerm,77] (* Shenghui Yang, May 04 2025 *)
  • PARI
    for(n=1, 100, print1(denominator(direuler(p=2, n, 1/(1-X)^(3/2))[n]), ", "))

Formula

Sum_{k=1..n} A383657(k)/A383658(k) ~ 2*n*sqrt(log(n)/Pi) * (1 - (1 - 3*gamma/2)/(2*log(n))), where gamma is the Euler-Mascheroni constant A001620.

A383793 Numerators of Dirichlet g.f.: Sum_{n>=1} a(n)/n^s = zeta(s-1)^(1/3).

Original entry on oeis.org

1, 2, 1, 8, 5, 2, 7, 112, 2, 10, 11, 8, 13, 14, 5, 560, 17, 4, 19, 40, 7, 22, 23, 112, 50, 26, 14, 56, 29, 10, 31, 2912, 11, 34, 35, 16, 37, 38, 13, 560, 41, 14, 43, 88, 10, 46, 47, 560, 98, 100, 17, 104, 53, 28, 55, 784, 19, 58, 59, 40, 61, 62, 14, 46592, 65
Offset: 1

Views

Author

Vaclav Kotesovec, May 10 2025

Keywords

Comments

General formula: if k >= 0, m > 0, and the Dirichlet generating function is zeta(s-k)^m * f(s), where f(s) has all possible poles at points less than k+1, then Sum_{j=1..n} a(j) ~ n^(k+1) * log(n)^(m-1) * f(k+1) / ((k+1) * Gamma(m)) * (1 + (m-1)*(m*gamma - 1/(k+1) + f'(k+1)/f(k+1)) / log(n)), where gamma is the Euler-Mascheroni constant A001620 and Gamma() is the Gamma function.

Crossrefs

Cf. A256688, A256689, A257099, A383705, A383794 (denominators).

Programs

  • PARI
    for(n=1, 100, print1(numerator(direuler(p=2, n, 1/(1-p*X)^(1/3))[n]), ", "))

Formula

Sum_{k=1..n} A383793(k) / A383794(k) ~ n^2 / (2*Gamma(1/3)*log(n)^(2/3)) * (1 + (1 - 2*gamma/3)/(3*log(n))), where gamma is the Euler-Mascheroni constant A001620 and Gamma() is the Gamma function.

A383794 Denominators of Dirichlet g.f.: Sum_{n>=1} a(n)/n^s = zeta(s-1)^(1/3).

Original entry on oeis.org

1, 3, 1, 9, 3, 3, 3, 81, 1, 9, 3, 9, 3, 9, 3, 243, 3, 3, 3, 27, 3, 9, 3, 81, 9, 9, 3, 27, 3, 9, 3, 729, 3, 9, 9, 9, 3, 9, 3, 243, 3, 9, 3, 27, 3, 9, 3, 243, 9, 27, 3, 27, 3, 9, 9, 243, 3, 9, 3, 27, 3, 9, 3, 6561, 9, 9, 3, 27, 3, 27, 3, 81, 3, 9, 9, 27, 9, 9, 3, 729
Offset: 1

Views

Author

Vaclav Kotesovec, May 10 2025

Keywords

Crossrefs

Cf. A256688, A256689, A257099, A383705, A383793 (numerators).

Programs

  • PARI
    for(n=1, 100, print1(denominator(direuler(p=2, n, 1/(1-p*X)^(1/3))[n]), ", "))
Previous Showing 11-14 of 14 results.