A069265 Numbers k such that Sum_{d|k} d/core(d) > k, where core(d) is the squarefree part of d.
4, 8, 9, 16, 18, 25, 32, 36, 48, 49, 50, 64, 72, 81, 98, 100, 108, 121, 128, 144, 162, 169, 192, 196, 200, 225, 242, 256, 288, 289, 300, 324, 338, 361, 392, 400, 432, 441, 450, 484, 512, 529, 576, 578, 588, 625, 648, 676, 722, 729, 768, 784, 800, 841, 882, 900
Offset: 1
Links
- Amiram Eldar, Table of n, a(n) for n = 1..10000
Programs
-
Mathematica
f[p_, e_] := If[OddQ[e], 2*(p^(e + 1) - 1)/(p^2 - 1), (p^(e + 2) + p^e - 2)/(p^2 - 1)]; Select[Range[2, 1000], Times @@ (f @@@ FactorInteger[#]) > # &] (* Amiram Eldar, Sep 03 2020 *)
Formula
k such that A068976(k) > k.