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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.

A260020 Numbers n such that 2*phi(n) = phi(2*sigma(n)).

Table of values

n a(n)
1 2
2 3
3 8
4 9
5 15
6 26
7 39
8 45
9 74
10 104
11 111
12 117
13 122
14 128
15 146
16 175
17 183
18 195
19 219
20 296
21 314
22 333
23 357
24 386
25 471
26 488
27 549
28 554
29 555
30 579
31 584
32 585
33 608
34 626
35 646
36 657
37 794
38 831
39 842
40 914
41 915
42 939
43 962
44 1071
45 1082
46 1095
47 1191
48 1226
49 1256
50 1263
51 1292
52 1322

List of values

[2, 3, 8, 9, 15, 26, 39, 45, 74, 104, 111, 117, 122, 128, 146, 175, 183, 195, 219, 296, 314, 333, 357, 386, 471, 488, 549, 554, 555, 579, 584, 585, 608, 626, 646, 657, 794, 831, 842, 914, 915, 939, 962, 1071, 1082, 1095, 1191, 1226, 1256, 1263, 1292, 1322]

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

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