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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.

A039654 a(n) = prime reached by iterating f(x) = sigma(x)-1 starting at n, or -1 if no prime is ever reached.

Table of values

n a(n)
2 2
3 3
4 11
5 5
6 11
7 7
8 23
9 71
10 17
11 11
12 71
13 13
14 23
15 23
16 71
17 17
18 59
19 19
20 41
21 31
22 47
23 23
24 59
25 71
26 41
27 71
28 71
29 29
30 71
31 31
32 167
33 47
34 53
35 47
36 233
37 37
38 59
39 71
40 89
41 41
42 167
43 43
44 83
45 167
46 71
47 47
48 167
49 167
50 167
51 71
52 97
53 53
54 167
55 71
56 167
57 79
58 89
59 59
60 167
61 61
62 167
63 103
64 311
65 83
66 167
67 67

List of values

[2, 3, 11, 5, 11, 7, 23, 71, 17, 11, 71, 13, 23, 23, 71, 17, 59, 19, 41, 31, 47, 23, 59, 71, 41, 71, 71, 29, 71, 31, 167, 47, 53, 47, 233, 37, 59, 71, 89, 41, 167, 43, 83, 167, 71, 47, 167, 167, 167, 71, 97, 53, 167, 71, 167, 79, 89, 59, 167, 61, 167, 103, 311, 83, 167, 67]

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

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