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

Author

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

Keywords

• nonn
• easy

Comments

A006039 lists the primitive nondeficient numbers.

The first odd term is 4725.

Examples

			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;
		

Links

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

Crossrefs

A006039 is used to define this sequence.

Subsequence of: A091192.

A337689 is a subsequence.

A337690 is used in a formula defining this sequence.

Programs

PARI

See Corneth link \\ David A. Corneth, Oct 07 2020

Formula

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