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.

A349124 a(n) = A349123(n) / A003557(n), where A349123 is the Dirichlet convolution of the arithmetic derivative with n*tau(n).

Original entry on oeis.org

0, 1, 1, 4, 1, 15, 1, 10, 4, 21, 1, 48, 1, 27, 24, 20, 1, 42, 1, 72, 30, 39, 1, 110, 4, 45, 10, 96, 1, 279, 1, 35, 42, 57, 36, 120, 1, 63, 48, 170, 1, 369, 1, 144, 78, 75, 1, 210, 4, 54, 60, 168, 1, 90, 48, 230, 66, 93, 1, 828, 1, 99, 102, 56, 54, 549, 1, 216, 78, 531, 1, 260, 1, 117, 66, 240, 54, 639, 1, 330, 20, 129
Offset: 1

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Author

Antti Karttunen, Nov 08 2021

Keywords

Crossrefs

Programs

  • Mathematica
    f[p_, e_] := p^(e - 1); s[1] = 1; s[n_] := Times @@ f @@@ FactorInteger[n]; d[1] = 0; d[n_] := n*Plus @@ ((Last[#]/First[#]) & /@ FactorInteger[n]); a[n_] := DivisorSum[n, d[#]*(n/#)*DivisorSigma[0, n/#] &] / s[n]; Array[a, 100] (* Amiram Eldar, Nov 08 2021 *)
  • PARI
    A003557(n) = (n/factorback(factorint(n)[, 1]));
    A349124(n) = (A349123(n) / A003557(n)); \\ Needs also code from A349123.

Formula

a(n) = A349123(n) / A003557(n).