cp's OEIS Frontend

A337689 Numbers divisible by 3 or more primitive nondeficient numbers.

%I A337689 #17 Oct 19 2020 04:23:29
%S A337689 140,280,420,560,700,840,980,1120,1144,1260,1320,1400,1540,1560,1680,
%T A337689 1820,1848,1890,1960,2100,2184,2200,2240,2288,2380,2520,2600,2640,
%U A337689 2660,2800,2860,2940,2992,3080,3120,3150,3220,3300,3344,3360,3432,3500,3640,3696,3740
%N A337689 Numbers divisible by 3 or more primitive nondeficient numbers.
%C A337689 A006039 lists the primitive nondeficient numbers.
%H A337689 David A. Corneth, <a href="/A337689/b337689.txt">Table of n, a(n) for n = 1..10000</a>
%H A337689 David A. Corneth, <a href="/A337689/a337689.gp.txt">PARI program</a>
%F A337689 Numbers k such that A337690(k) >= 3.
%e A337689 Table of n, a(n) and the relevant divisors starts:
%e A337689    n   a(n)   divisors in A006039
%e A337689    1    140   20, 28, 70;
%e A337689    2    280   20, 28, 70;
%e A337689    3    420   6, 20, 28, 70;
%e A337689    4    560   20, 28, 70;
%e A337689    5    700   20, 28, 70;
%e A337689    6    840   6, 20, 28, 70;
%e A337689    7    980   20, 28, 70;
%e A337689    8   1120   20, 28, 70;
%e A337689    9   1144   88, 104, 572;
%e A337689   10   1260   6, 20, 28, 70;
%e A337689   11   1320   6, 20, 88;
%e A337689   12   1400   20, 28, 70;
%o A337689 (PARI) See Corneth link \\ _David A. Corneth_, Oct 07 2020
%Y A337689 A006039, A337690 are used in a definition of this sequence.
%Y A337689 Subsequence of: A337688.
%K A337689 nonn,easy
%O A337689 1,1
%A A337689 _David A. Corneth_, _Antti Karttunen_ and _Peter Munn_, Sep 20 2020