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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.

A258409 Greatest common divisor of all (d-1)'s, where the d's are the positive divisors of n.

Table of values

n a(n)
2 1
3 2
4 1
5 4
6 1
7 6
8 1
9 2
10 1
11 10
12 1
13 12
14 1
15 2
16 1
17 16
18 1
19 18
20 1
21 2
22 1
23 22
24 1
25 4
26 1
27 2
28 1
29 28
30 1
31 30
32 1
33 2
34 1
35 2
36 1
37 36
38 1
39 2
40 1
41 40
42 1
43 42
44 1
45 2
46 1
47 46
48 1
49 6
50 1
51 2
52 1
53 52
54 1
55 2
56 1
57 2
58 1
59 58
60 1
61 60
62 1
63 2
64 1
65 4
66 1
67 66
68 1
69 2
70 1
71 70
72 1
73 72
74 1
75 2
76 1
77 2
78 1
79 78
80 1

List of values

[1, 2, 1, 4, 1, 6, 1, 2, 1, 10, 1, 12, 1, 2, 1, 16, 1, 18, 1, 2, 1, 22, 1, 4, 1, 2, 1, 28, 1, 30, 1, 2, 1, 2, 1, 36, 1, 2, 1, 40, 1, 42, 1, 2, 1, 46, 1, 6, 1, 2, 1, 52, 1, 2, 1, 2, 1, 58, 1, 60, 1, 2, 1, 4, 1, 66, 1, 2, 1, 70, 1, 72, 1, 2, 1, 2, 1, 78, 1]

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