Halve it if even, triple it and add 1 if odd: how long until you reach 1?

Name: Halve it if even, triple it and add 1 if odd: how long until you reach 1?
Creator: Unlabeled
License: Original computation by Unlabeled; nothing copied from the source

Starting from 27 takes 111 steps and climbs as high as 9,232 on the way down to 1. Its neighbors 26 and 28 need 10 and 18.

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y ↑: Steps to reach 1 (count)
x →: Starting number (value)

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The data: 40 points

Starting number (value)	Steps to reach 1 (count)
1	0
2	1
3	7
4	2
5	5
6	8
7	16
8	3
9	19
10	6
11	14
12	9
13	9
14	17
15	17
16	4
17	12
18	20
19	20
20	7
21	7
22	15
23	15
24	10
25	23
26	10
27	111
28	18
29	18
30	18
31	106
32	5
33	26
34	13
35	13
36	21
37	21
38	21
39	34
40	8

Source: Computed: the Collatz (3x + 1) rule applied to each starting number (Lagarias 1985; OEIS A006577)
Licence: Original computation by Unlabeled; nothing copied from the source
Read: 2026-09-29
Drawn: 40 points as the puzzle showed them · scatter

Ran in puzzle #23 on October 19, 2026. Play it

Starting number (value)	Steps to reach 1 (count)
1	0
2	1
3	7
4	2
5	5
6	8
7	16
8	3
9	19
10	6
11	14
12	9
13	9
14	17
15	17
16	4
17	12
18	20
19	20
20	7
21	7
22	15
23	15
24	10
25	23
26	10
27	111
28	18
29	18
30	18
31	106
32	5
33	26
34	13
35	13
36	21
37	21
38	21
39	34
40	8

Starting number (value)	Steps to reach 1 (count)
1	0
2	1
3	7
4	2
5	5
6	8
7	16
8	3
9	19
10	6
11	14
12	9
13	9
14	17
15	17
16	4
17	12
18	20
19	20
20	7
21	7
22	15
23	15
24	10
25	23
26	10
27	111
28	18
29	18
30	18
31	106
32	5
33	26
34	13
35	13
36	21
37	21
38	21
39	34
40	8

Halve it if even, triple it and add 1 if odd: how long until you reach 1?

More like this

Starting number (value)	Steps to reach 1 (count)
1	0
2	1
3	7
4	2
5	5
6	8
7	16
8	3
9	19
10	6
11	14
12	9
13	9
14	17
15	17
16	4
17	12
18	20
19	20
20	7
21	7
22	15
23	15
24	10
25	23
26	10
27	111
28	18
29	18
30	18
31	106
32	5
33	26
34	13
35	13
36	21
37	21
38	21
39	34
40	8