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.

A109424 Numbers n such that sigma(n)/bigomega(n) is not an integer [sigma(n) = sum of divisors of n; bigomega(n) = number of prime divisors of n, counted with multiplicity].

Table of values

n a(n)
1 4
2 9
3 12
4 16
5 25
6 27
7 28
8 32
9 36
10 40
11 48
12 49
13 52
14 63
15 64
16 75
17 76
18 80
19 81
20 90
21 100
22 104
23 112
24 117
25 121
26 124
27 128
28 136
29 144
30 148
31 162
32 169
33 171
34 172
35 175
36 176
37 180
38 192
39 196
40 208
41 225
42 232
43 234
44 243
45 244
46 252
47 256
48 268
49 272
50 273
51 279
52 289
53 292
54 296
55 300
56 306
57 316

List of values

[4, 9, 12, 16, 25, 27, 28, 32, 36, 40, 48, 49, 52, 63, 64, 75, 76, 80, 81, 90, 100, 104, 112, 117, 121, 124, 128, 136, 144, 148, 162, 169, 171, 172, 175, 176, 180, 192, 196, 208, 225, 232, 234, 243, 244, 252, 256, 268, 272, 273, 279, 289, 292, 296, 300, 306, 316]

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

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