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.

A294975 a(n) = (1/(24*n)) * Sum_{d|n} A008683(n/d) * (A288840(d) - A288877(d)).

Original entry on oeis.org

30, 11775, 4261790, 1712983575, 733856931102, 327479190724415, 150310619778297630, 70428822637214055855, 33523597190372498303390, 16156445902947621421555071, 7865129058155113639991368350, 3860735065245244345161225213335
Offset: 1

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Author

Seiichi Manyama, Feb 12 2018

Keywords

Crossrefs

Programs

  • Mathematica
    terms = 12;
    E2[x_] = 1 - 24*Sum[k*x^k/(1 - x^k), {k, 1, terms}];
    E4[x_] = 1 + 240*Sum[k^3*x^k/(1 - x^k), {k, 1, terms}];
    E6[x_] = 1 - 504*Sum[k^5*x^k/(1 - x^k), {k, 1, terms}];
    E8[x_] = 1 + 480*Sum[k^7*x^k/(1 - x^k), {k, 1, terms}];
    a[n_] := (1/(24 n))*Sum[MoebiusMu[n/d]*SeriesCoefficient[E8[x]/E6[x] - E4[x]/E2[x], {x, 0, d}], {d, Divisors[n]}];
    Array[a, terms] (* Jean-François Alcover, Feb 26 2018 *)

Formula

a(n) ~ exp(2*Pi*n) / (12*n). - Vaclav Kotesovec, Jun 03 2018