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.

A326807 Numbers m such that s(m)/m > s(k)/k for all k < m, where s(m) = A168512(m) is the sum of divisors of m, weighted by divisor multiplicity.

Original entry on oeis.org

1, 2, 4, 8, 12, 16, 24, 36, 72, 120, 180, 240, 360, 720, 840, 1260, 1680, 2520, 5040, 10080, 15120, 25200, 27720, 55440, 110880, 166320, 277200, 332640, 554400, 665280, 720720, 1441440, 2162160, 3603600, 4324320, 7207200, 8648640, 10810800, 21621600, 36756720, 61261200, 73513440
Offset: 1

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Author

Amiram Eldar, Oct 19 2019

Keywords

Comments

The least number m such that A168512(m)/m > k, for k = 2, 3, ... is 4, 120, 27720, 122522400, ...

Crossrefs

Programs

  • Mathematica
    s[n_] := 1 + DivisorSum[n, #*IntegerExponent[n, #] &, # > 1 &]; seq = {}; sm = 0; Do[s1 = s[n]/n; If[s1 > sm, sm = s1; AppendTo[seq, n]], {n, 1, 100000000}]; seq (* after Michael De Vlieger at A168512 *)