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.

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A276480 a(n) = the smallest number k such that floor(Sum_{d|k} 0.d) = n.

Original entry on oeis.org

1, 6, 18, 36, 72, 120, 168, 288, 420, 360, 792, 720, 1512, 1260, 1440, 3240, 4032, 2880, 2520, 3960, 5544, 6720, 5040, 10920, 7560, 14400, 10080, 13860, 15840, 15120, 18480, 20160, 37440, 25200, 46800, 30240, 36960, 32760, 27720, 71280, 50400, 69300, 60480
Offset: 0

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Author

Jaroslav Krizek, Sep 05 2016

Keywords

Comments

Here 0.d means the decimal fraction obtained by writing d after the decimal point, e.g., 0.12 = 12/100 = 3/25.
a(n) = the smallest number k such that floor (A276466(k)/A276467(k)) = n.
The first few values of Sum_{d|n} 0.d are 1/10, 3/10, 2/5, 7/10, 3/5, 6/5, 4/5, 3/2, 13/10, 9/10, 21/100, 43/25, ...

Crossrefs

Programs

  • Mathematica
    Table[k = 1; While[Floor@ Total@ (#*1/10^(1 + Floor@ Log10@ #)) != n &@ Divisors@ k, k++]; k, {n, 0, 40}] (* Michael De Vlieger, Sep 06 2016 *)
  • PARI
    a(n) = {k = 1; while(floor(sumdiv(k, d, d/10^(#Str(d)))) != n, k++); k; } \\ Michel Marcus, Sep 05 2016
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