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URL: https://oeis.org/A337689

⇱ A337689 - OEIS

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A337689
Numbers divisible by 3 or more primitive nondeficient numbers.
4
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
OFFSET
1,1
COMMENTS
A006039 lists the primitive nondeficient numbers.
a(103) = 7150, a(150) = 10010 and a(293) = 17325 are the earliest terms expressible as a prime times a deficient number, and so absent from A389636. - Peter Munn, Jan 28 2026
LINKS
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
Subsequence of A337688.
Sequence in context: A090945 A140798 A325022 * A360217 A249554 A196447
KEYWORD
nonn,easy
AUTHOR
STATUS
approved