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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.

A008908 a(n) = (1 + number of halving and tripling steps to reach 1 in the Collatz (3x+1) problem), or -1 if 1 is never reached.

Table of values

n a(n)
1 1
2 2
3 8
4 3
5 6
6 9
7 17
8 4
9 20
10 7
11 15
12 10
13 10
14 18
15 18
16 5
17 13
18 21
19 21
20 8
21 8
22 16
23 16
24 11
25 24
26 11
27 112
28 19
29 19
30 19
31 107
32 6
33 27
34 14
35 14
36 22
37 22
38 22
39 35
40 9
41 110
42 9
43 30
44 17
45 17
46 17
47 105
48 12
49 25
50 25
51 25
52 12
53 12
54 113
55 113
56 20
57 33
58 20
59 33
60 20
61 20
62 108
63 108
64 7
65 28
66 28
67 28
68 15
69 15
70 15
71 103

List of values

[1, 2, 8, 3, 6, 9, 17, 4, 20, 7, 15, 10, 10, 18, 18, 5, 13, 21, 21, 8, 8, 16, 16, 11, 24, 11, 112, 19, 19, 19, 107, 6, 27, 14, 14, 22, 22, 22, 35, 9, 110, 9, 30, 17, 17, 17, 105, 12, 25, 25, 25, 12, 12, 113, 113, 20, 33, 20, 33, 20, 20, 108, 108, 7, 28, 28, 28, 15, 15, 15, 103]

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