cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A109428 Numbers n such that sigma(n)/omega(n) is not an integer [sigma(n) =sum of divisors of n; omega(n)=number of distinct prime factors of n].

Table of values

n a(n)
1 18
2 36
3 50
4 72
5 84
6 98
7 100
8 144
9 156
10 162
11 196
12 200
13 225
14 228
15 242
16 252
17 273
18 288
19 300
20 324
21 336
22 338
23 364
24 372
25 392
26 399
27 400
28 441
29 444
30 468
31 484
32 516
33 525
34 532
35 576
36 578
37 624
38 648
39 651
40 676
41 684
42 700
43 722
44 732
45 741
46 756
47 777
48 784
49 800
50 804
51 819
52 868
53 876

List of values

[18, 36, 50, 72, 84, 98, 100, 144, 156, 162, 196, 200, 225, 228, 242, 252, 273, 288, 300, 324, 336, 338, 364, 372, 392, 399, 400, 441, 444, 468, 484, 516, 525, 532, 576, 578, 624, 648, 651, 676, 684, 700, 722, 732, 741, 756, 777, 784, 800, 804, 819, 868, 876]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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