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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.

A078892 Numbers n such that phi(n) - 1 is prime, where phi is Euler's totient function (A000010).

Table of values

n a(n)
1 5
2 7
3 8
4 9
5 10
6 12
7 13
8 14
9 15
10 16
11 18
12 19
13 20
14 21
15 24
16 25
17 26
18 27
19 28
20 30
21 31
22 33
23 35
24 36
25 38
26 39
27 42
28 43
29 44
30 45
31 49
32 50
33 51
34 52
35 54
36 56
37 61
38 62
39 64
40 65
41 66
42 68
43 69
44 70
45 72
46 73
47 77
48 78
49 80
50 81
51 84
52 86
53 90
54 91
55 92
56 93
57 95
58 96
59 98
60 99
61 102
62 103
63 104
64 105
65 109
66 111
67 112
68 117

List of values

[5, 7, 8, 9, 10, 12, 13, 14, 15, 16, 18, 19, 20, 21, 24, 25, 26, 27, 28, 30, 31, 33, 35, 36, 38, 39, 42, 43, 44, 45, 49, 50, 51, 52, 54, 56, 61, 62, 64, 65, 66, 68, 69, 70, 72, 73, 77, 78, 80, 81, 84, 86, 90, 91, 92, 93, 95, 96, 98, 99, 102, 103, 104, 105, 109, 111, 112, 117]

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

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