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.

A358765 a(n) = A003415(n)*A276086(n) mod 60, where A003415 is the arithmetic derivative and A276086 is the primorial base exp-function.

Original entry on oeis.org

0, 0, 3, 6, 36, 18, 25, 10, 0, 0, 15, 30, 40, 50, 15, 0, 0, 30, 45, 10, 0, 0, 45, 30, 20, 20, 45, 30, 0, 30, 37, 14, 0, 48, 57, 12, 0, 10, 45, 0, 0, 30, 35, 50, 0, 30, 15, 30, 20, 20, 45, 0, 0, 30, 15, 20, 0, 0, 45, 30, 8, 38, 51, 54, 12, 36, 5, 10, 0, 0, 15, 30, 0, 50, 45, 30, 0, 0, 55, 10, 0, 0, 15
Offset: 0

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Author

Antti Karttunen, Dec 06 2022

Keywords

Crossrefs

Cf. A016825 (positions of odd terms), A042965 (of even terms), A235992 (of multiples of 4), A067019 (of terms of the form 4k+2).

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); };
    A358765(n) = ((A003415(n)*A276086(n))%60);

Formula

a(n) = A358669(n) mod 60.