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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.

A378642 Number of numbers m <= n such that phi(m) does not divide n, where phi is the Euler totient function (A000010).

Table of values

n a(n)
1 0
2 0
3 1
4 0
5 3
6 1
7 5
8 1
9 7
10 5
11 9
12 1
13 11
14 9
15 13
16 5
17 15
18 9
19 17
20 10
21 19
22 17
23 21
24 5
25 23
26 21
27 25
28 19
29 27
30 19
31 29
32 16
33 31
34 29
35 33
36 16
37 35
38 33
39 37
40 22
41 39
42 33
43 41
44 34
45 43
46 41
47 45
48 16
49 47
50 43
51 49
52 43
53 51
54 41
55 53
56 41
57 55
58 53
59 57
60 34
61 59
62 57
63 61
64 42
65 63
66 55
67 65
68 59
69 67
70 63

List of values

[0, 0, 1, 0, 3, 1, 5, 1, 7, 5, 9, 1, 11, 9, 13, 5, 15, 9, 17, 10, 19, 17, 21, 5, 23, 21, 25, 19, 27, 19, 29, 16, 31, 29, 33, 16, 35, 33, 37, 22, 39, 33, 41, 34, 43, 41, 45, 16, 47, 43, 49, 43, 51, 41, 53, 41, 55, 53, 57, 34, 59, 57, 61, 42, 63, 55, 65, 59, 67, 63]

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

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