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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.

A383131 a(n) is the number of iterations that n requires to reach 1 under the map x -> -x/2 if x is even, 3x + 1 if x is odd; a(n) = -1 if 1 is never reached.

Table of values

n a(n)
1 0
2 3
3 12
4 2
5 5
6 5
7 8
8 5
9 11
10 11
11 50
12 14
13 14
14 14
15 53
16 4
17 17
18 17
19 43
20 7
21 7
22 7
23 20
24 7
25 46
26 46
27 59
28 10
29 10
30 10
31 23
32 7
33 49
34 49
35 62
36 13
37 13
38 13
39 13
40 13
41 26
42 26
43 39
44 52
45 52
46 52
47 65
48 16
49 16
50 16
51 78
52 16
53 16
54 16
55 29
56 16
57 42
58 42
59 55
60 55
61 55
62 55
63 68
64 6
65 19
66 19
67 19
68 19
69 19

List of values

[0, 3, 12, 2, 5, 5, 8, 5, 11, 11, 50, 14, 14, 14, 53, 4, 17, 17, 43, 7, 7, 7, 20, 7, 46, 46, 59, 10, 10, 10, 23, 7, 49, 49, 62, 13, 13, 13, 13, 13, 26, 26, 39, 52, 52, 52, 65, 16, 16, 16, 78, 16, 16, 16, 29, 16, 42, 42, 55, 55, 55, 55, 68, 6, 19, 19, 19, 19, 19]

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