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A337689 Numbers divisible by 3 or more primitive nondeficient numbers. 3
140, 280, 420, 560, 700, 840, 980, 1120, 1144, 1260, 1320, 1400, 1540, 1560, 1680, 1820, 1848, 1890, 1960, 2100, 2184, 2200, 2240, 2288, 2380, 2520, 2600, 2640, 2660, 2800, 2860, 2940, 2992, 3080, 3120, 3150, 3220, 3300, 3344, 3360, 3432, 3500, 3640, 3696, 3740 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A006039 lists the primitive nondeficient numbers.

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) >= 3.

EXAMPLE

Table of n, a(n) and the relevant divisors starts:

   n   a(n)   divisors in A006039

   1    140   20, 28, 70;

   2    280   20, 28, 70;

   3    420   6, 20, 28, 70;

   4    560   20, 28, 70;

   5    700   20, 28, 70;

   6    840   6, 20, 28, 70;

   7    980   20, 28, 70;

   8   1120   20, 28, 70;

   9   1144   88, 104, 572;

  10   1260   6, 20, 28, 70;

  11   1320   6, 20, 88;

  12   1400   20, 28, 70;

PROG

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

CROSSREFS

A006039, A337690 are used in a definition of this sequence.

Subsequence of: A337688.

Sequence in context: A090945 A140798 A325022 * A249554 A196447 A255783

Adjacent sequences:  A337686 A337687 A337688 * A337690 A337691 A337692

KEYWORD

nonn,easy

AUTHOR

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

STATUS

approved

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Last modified September 17 19:58 EDT 2021. Contains 347489 sequences. (Running on oeis4.)