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.

A322872 Ordinal transform of A171462, where A171462(n) = n - A052126(n).

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 1, 3, 2, 1, 1, 2, 1, 2, 3, 3, 1, 4, 1, 2, 2, 1, 1, 3, 2, 1, 3, 2, 1, 3, 1, 4, 2, 1, 3, 4, 1, 2, 3, 2, 1, 4, 1, 2, 5, 1, 1, 3, 2, 3, 1, 2, 1, 6, 1, 3, 1, 1, 1, 4, 1, 2, 2, 4, 3, 4, 1, 1, 2, 5, 1, 5, 1, 2, 6, 3, 2, 4, 1, 2, 3, 1, 1, 5, 2, 1, 2, 3, 1, 6, 3, 2, 1, 1, 2, 3, 1, 4, 3, 4, 1, 2, 1, 3, 4
Offset: 1

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Author

Antti Karttunen, Dec 29 2018

Keywords

Crossrefs

Programs

  • Mathematica
    A171462[n_] := If[n == 1, 0, Module[{f = FactorInteger[n], p},
         p = f[[-1, 1]]; n(p-1)/p]];
    b[_] = 0;
    a[n_] := a[n] = With[{t = A171462[n]}, b[t] = b[t]+1];
    Array[a, 105] (* Jean-François Alcover, Dec 21 2021 *)
  • PARI
    up_to = 65537;
    ordinal_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), pt); for(i=1, length(invec), if(mapisdefined(om,invec[i]), pt = mapget(om, invec[i]), pt = 0); outvec[i] = (1+pt); mapput(om,invec[i],(1+pt))); outvec; };
    A171462(n) = if(1==n,0,(n-(n/vecmax(factor(n)[, 1]))));
    v322872 = ordinal_transform(vector(up_to,n,A171462(n)));
    A322872(n) = v322872[n];