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

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

k such that A068976(k) > k.

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 *)

Crossrefs

Cf. A068976, A007913.

Sequence in context: A166402 A255586 A034038 * A336359 A371013 A359680

Adjacent sequences: A069262 A069263 A069264 * A069266 A069267 A069268

Keyword

easy,nonn

Author

Benoit Cloitre, Apr 14 2002

Status

approved