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.

A348654 Indices of records in the sequence of unitary harmonic means A103339(k)/A103340(k).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 28, 30, 42, 60, 84, 105, 120, 140, 180, 210, 330, 390, 420, 660, 780, 840, 1092, 1155, 1260, 1540, 1820, 1980, 2310, 2730, 3570, 3990, 4290, 4620, 5460, 7140, 7980, 8580, 9240, 10920, 13860, 16380, 20020, 23940, 25740, 27720, 30030
Offset: 1

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Author

Amiram Eldar, Oct 28 2021

Keywords

Examples

			The unitary harmonic means of the first 6 positive integers are 1 < 4/3 < 3/2 < 8/5 < 5/3 < 2. The next record, A103339(10)/A103340(10) = 20/9, occurs at 10. Therefore, the first 7 terms of this sequence are 1, 2, 3, 4, 5, 6 and 10.
		

Crossrefs

The unitary version of A179971.

Programs

  • Mathematica
    f[p_, e_] := 2/(1 + p^(-e)); uhmeam[n_] := Times @@ f @@@ FactorInteger[n]; s = {}; max = 0; Do[u1 = uhmeam[n]; If[u1 > max, max = u1; AppendTo[s, n]], {n, 1, 10^5}]; s