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.

A286478 Ordinal transform of A034968, factorial base digit sum.

Original entry on oeis.org

1, 1, 2, 1, 2, 1, 3, 3, 4, 2, 3, 1, 5, 4, 5, 2, 3, 1, 6, 4, 5, 2, 3, 1, 4, 6, 7, 7, 8, 6, 8, 9, 10, 7, 8, 4, 11, 9, 10, 5, 6, 2, 11, 7, 8, 3, 4, 1, 9, 12, 13, 12, 13, 9, 14, 14, 15, 10, 11, 5, 16, 12, 13, 6, 7, 2, 14, 8, 9, 3, 4, 1, 15, 17, 18, 15, 16, 10, 19, 17, 18, 11, 12, 5, 19, 13, 14, 6, 7, 2, 15, 8, 9, 3, 4, 1, 20, 20, 21, 16, 17, 10, 22, 18, 19, 11, 12
Offset: 0

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Author

Antti Karttunen, May 20 2017

Keywords

Crossrefs

Cf. A000142, A034968, A254524 (base-10 analog).

Programs

  • Mathematica
    f[n_] := If[n == 0, 0, Module[{s = 0, i = 2, k = n},
         While[k>0, k = Floor[n/i!]; s += (i-1) k; i++]; n-s]];
    b[_] = 1;
    a[n_] := a[n] = With[{t = f[n]}, b[t]++];
    a /@ Range[0, 100] (* Jean-François Alcover, Dec 19 2021 *)

Formula

For all n>= 1, a(A000142(n)) = n.