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.

A369009 a(n) = A342001(n) - A083345(n).

Original entry on oeis.org

0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 2, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 2, 8, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 12, 0, 0, 0, 7, 0, 0, 0, 14, 0, 6, 0, 0, 0, 0, 0, 23, 0, 0, 0, 3, 0, 0, 0, 18, 0, 0, 0, 0, 0, 0, 0, 20, 0, 0, 0, 11, 0, 0, 0, 31, 0, 0, 0, 0, 0, 0, 0, 24, 0, 0, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 0, 10
Offset: 1

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Author

Antti Karttunen, Jan 14 2024

Keywords

Comments

Arithmetic derivative of n without its "inherited divisor" minus the arithmetic derivative of n without its greatest common divisor with n.

Crossrefs

Cf. A342090 (positions of terms > 0).

Programs

  • PARI
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A003557(n) = (n/factorback(factorint(n)[, 1]));
    A369009(n) = { my(u=A003415(n)); (u/A003557(n))-(u/gcd(n,u)); };