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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.

A066831 Numbers k such that sigma(k) divides sigma(phi(k)).

Table of values

n a(n)
1 1
2 13
3 71
4 87
5 89
6 181
7 203
8 305
9 319
10 362
11 667
12 899
13 1257
14 1363
15 1421
16 1525
17 1711
18 1798
19 1889
20 2407
21 2501
22 2933
23 3103
24 4609
25 4615
26 4687
27 4843
28 5002
29 5191
30 6583
31 7123
32 7625
33 7627
34 9374
35 9947
36 10063
37 10411
38 10991
39 11107
40 12989
41 13543
42 13891
43 14587

List of values

[1, 13, 71, 87, 89, 181, 203, 305, 319, 362, 667, 899, 1257, 1363, 1421, 1525, 1711, 1798, 1889, 2407, 2501, 2933, 3103, 4609, 4615, 4687, 4843, 5002, 5191, 6583, 7123, 7625, 7627, 9374, 9947, 10063, 10411, 10991, 11107, 12989, 13543, 13891, 14587]

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

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