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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.

A253473 a(n) = phi(c(n)) - tau(phi(c(n))), where c(n) is the n-th composite number.

Table of values

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

List of values

[0, 0, 1, 2, 1, 1, 2, 4, 4, 2, 4, 6, 6, 4, 14, 6, 12, 6, 4, 11, 14, 11, 16, 6, 12, 16, 11, 6, 14, 16, 18, 11, 34, 14, 26, 16, 12, 32, 16, 27, 22, 11, 22, 27, 26, 38, 14, 26, 38, 16, 16, 27, 32, 27, 48, 16, 26, 46, 32, 16, 57, 34, 48, 32, 16, 60, 38, 48, 42, 60]

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

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