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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.

A243997 a(n) = phi(sigma(n) - phi(n) - d(n)), where phi(n) is the Euler totient function, sigma(n) the sum of divisors of n and d(n) the number of divisors of n.

Table of values

n a(n)
1 1
2 0
3 0
4 1
5 0
6 2
7 0
8 6
9 2
10 4
11 0
12 6
13 0
14 6
15 4
16 6
17 0
18 18
19 0
20 12
21 8
22 10
23 0
24 20
25 4
26 12
27 6
28 18
29 0
30 24
31 0
32 40
33 8
34 16
35 8
36 24
37 0
38 18
39 12
40 20
41 0
42 36
43 0
44 28
45 16
46 22
47 0
48 42
49 4
50 66
51 12
52 32
53 0
54 46
55 12
56 40
57 16
58 28
59 0
60 48
61 0
62 30
63 30
64 40
65 16
66 56
67 0
68 40
69 16
70 48
71 0
72 104
73 0
74 36

List of values

[1, 0, 0, 1, 0, 2, 0, 6, 2, 4, 0, 6, 0, 6, 4, 6, 0, 18, 0, 12, 8, 10, 0, 20, 4, 12, 6, 18, 0, 24, 0, 40, 8, 16, 8, 24, 0, 18, 12, 20, 0, 36, 0, 28, 16, 22, 0, 42, 4, 66, 12, 32, 0, 46, 12, 40, 16, 28, 0, 48, 0, 30, 30, 40, 16, 56, 0, 40, 16, 48, 0, 104, 0, 36]

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