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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.

A072455 Number of totients in the reduced residue system of 2n-1.

Table of values

n a(n)
1 1
2 2
3 3
4 4
5 4
6 6
7 7
8 4
9 8
10 9
11 7
12 11
13 10
14 8
15 13
16 14
17 9
18 11
19 16
20 10
21 17
22 18
23 9
24 20
25 19
26 13
27 22
28 17
29 15
30 25
31 26
32 14
33 21
34 28
35 16
36 29
37 30
38 14
39 23
40 31
41 19
42 33
43 27
44 19
45 35
46 28
47 22
48 29
49 37
50 19
51 38
52 39
53 16
54 41
55 42
56 26
57 44
58 33
59 26
60 38
61 41
62 27
63 36
64 47
65 29
66 49
67 43
68 22
69 51
70 52
71 32
72 43
73 40
74 27

List of values

[1, 2, 3, 4, 4, 6, 7, 4, 8, 9, 7, 11, 10, 8, 13, 14, 9, 11, 16, 10, 17, 18, 9, 20, 19, 13, 22, 17, 15, 25, 26, 14, 21, 28, 16, 29, 30, 14, 23, 31, 19, 33, 27, 19, 35, 28, 22, 29, 37, 19, 38, 39, 16, 41, 42, 26, 44, 33, 26, 38, 41, 27, 36, 47, 29, 49, 43, 22, 51, 52, 32, 43, 40, 27]

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