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.

A347389 Dirichlet convolution of A003415(n) and A003415(A276086(n)), where A003415(n) is the arithmetic derivative of n, and A276086(n) gives the prime product form of primorial base expansion of n.

Original entry on oeis.org

0, 1, 1, 5, 1, 11, 1, 22, 11, 29, 1, 48, 1, 17, 34, 76, 1, 84, 1, 160, 22, 137, 1, 172, 31, 61, 88, 130, 1, 404, 1, 456, 142, 725, 40, 411, 1, 297, 66, 900, 1, 1262, 1, 1984, 421, 4001, 1, 1244, 21, 1866, 730, 2382, 1, 6574, 160, 8740, 302, 22157, 1, 1930, 1, 43, 1249, 1530, 84, 2222, 1, 2968, 4006, 568, 1, 1860
Offset: 1

Views

Author

Antti Karttunen, Sep 02 2021

Keywords

Crossrefs

Cf. also A345000.

Programs

  • PARI
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    A347389(n) = sumdiv(n,d,A003415(n/d) * A003415(A276086(d)));

Formula

a(n) = Sum_{d|n} A003415(n/d) * A327860(d).