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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.

A337979 Define a map f(n):= n-> n + pi(n) - pi(n + pi(n)), where pi(n) is the prime count of n (n>=1). a(n) is the number of steps for n to reach 1 under repeated iteration of f.

Table of values

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

List of values

[0, 1, 2, 3, 4, 5, 6, 7, 7, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 14, 14, 15, 15, 16, 16, 17, 17, 17, 18, 18, 19, 19, 19, 20, 20, 20, 21, 21, 21, 22, 22, 22, 23, 23, 23, 24, 24, 24, 25, 25, 25, 25, 26, 26, 26, 26, 26, 27, 27, 27, 27, 28, 28, 28, 28, 28, 29, 29]

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