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.

A185358 The period of the sequence i^i (mod n) starts from i=a(n).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 3, 4, 1, 1, 1
Offset: 1

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Crossrefs

Cf. A185359.

Programs

  • Mathematica
    a[p_,e_]:=1- p*(1+Floor[-e/p]);a[n_]:=Max@Module[{fa=FactorInteger[n]},Table[a[fa[[i,1]],fa[[i,2]]],{i,1,Length[fa]}]];Table[a[n],{n,1,84}]
  • Python
    from sympy import factorint, floor
    def a(n):
        f=factorint(n)
        return 1 if n==1 else max(1 - i*(1 + (-f[i])//i) for i in f)
    print([a(n) for n in range(1, 201)]) # Indranil Ghosh, Jun 29 2017

Formula

If n = Product_{pi^ei} then a(n) = Max_{1- pi*(1+floor[-ei/pi])}.