A337688 Numbers divisible by 2 or more primitive nondeficient numbers.

60, 84, 120, 140, 168, 180, 210, 240, 252, 264, 280, 300, 312, 336, 360, 420, 440, 480, 504, 520, 528, 540, 560, 588, 600, 616, 624, 630, 660, 672, 700, 720, 728, 756, 780, 792, 816, 840, 880, 900, 912, 924, 936, 960, 980, 1008, 1020, 1040, 1050, 1056, 1080, 1092

Offset

1,1

Comments

A006039 lists the primitive nondeficient numbers.

The first odd term is 4725.

Links

David A. Corneth, Table of n, a(n) for n = 1..10000

David A. Corneth, PARI program

Formula

Numbers k such that A337690(k) >= 2.

Example

Table of n, a(n) and the relevant divisors starts:
   n   a(n)   divisors in A006039
   1     60   6, 20;
   2     84   6, 28;
   3    120   6, 20;
   4    140   20, 28, 70;
   5    168   6, 28;
   6    180   6, 20;
   7    210   6, 70;
   8    240   6, 20;
   9    252   6, 28;
  10    264   6, 88;
  11    280   20, 28, 70;
  12    300   6, 20;
  13    312   6, 104;
  14    336   6, 28;
  15    360   6, 20;
  16    420   6, 20, 28, 70;

Prog

(PARI) See Corneth link \\ David A. Corneth, Oct 07 2020

Crossrefs

A006039 is used to define this sequence.

Subsequence of: A091192.

A337689 is a subsequence.

A337690 is used in a formula defining this sequence.

Sequence in context: A350140 A379097 A291125 * A086975 A357686 A100659

Adjacent sequences: A337685 A337686 A337687 * A337689 A337690 A337691

Keyword

nonn,easy

Author

David A. Corneth, Antti Karttunen and Peter Munn, Sep 20 2020

Status

approved