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.

A258857 Seventh pi-based arithmetic derivative of n.

Original entry on oeis.org

0, 0, 0, 0, 4, 0, 4, 4, 2304, 2304, 0, 0, 12288, 4, 80, 208, 81920, 4, 208, 512, 81920, 80, 32, 512, 16092, 512, 208, 138240, 30848, 0, 2304, 0, 622592, 512, 0, 4, 3000, 2304, 4, 30848, 3000, 4, 16, 32, 114752, 2160, 4, 80, 772352, 936, 208, 332, 52056, 12288
Offset: 0

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Author

Alois P. Heinz, Jun 12 2015

Keywords

Crossrefs

Column k=7 of A258850.

Programs

  • Maple
    with(numtheory):
    d:= n-> n*add(i[2]*pi(i[1])/i[1], i=ifactors(n)[2]):
    A:= proc(n, k) option remember; `if`(k=0, n, d(A(n, k-1))) end:
    a:= n-> A(n, 7):
    seq(a(n), n=0..100);

Formula

a(n) = A258851^7(n).