A127885 - cp's OEIS frontend

A127885 a(n) = minimal number of steps to get from n to 1, where a step is x -> 3x+1 if x is odd, or x -> either x/2 or 3x+1 if x is even; or -1 if 1 is never reached.

n	a(n)
1	0
2	1
3	7
4	2
5	5
6	8
7	16
8	3
9	11
10	6
11	14
12	9
13	9
14	17
15	17
16	4
17	12
18	12
19	20
20	7
21	7
22	15
23	15
24	10
25	23
26	10
27	23
28	10
29	18
30	18
31	31
32	5
33	18
34	13
35	13
36	13
37	13
38	21
39	26
40	8
41	21
42	8
43	21
44	16
45	16
46	16
47	29
48	11
49	16
50	16
51	24
52	11
53	11
54	24
55	24
56	11
57	24
58	19
59	24
60	19
61	19
62	32
63	32
64	6
65	19
66	19
67	27
68	14
69	14
70	14
71	27
72	14
73	27
74	14
75	14
76	22
77	22
78	27
79	27
80	9
81	22
82	22
83	22
84	9
85	9
86	22
87	22
88	17
89	22
90	17
91	30
92	17
93	17
94	30
95	30
96	12
97	30
98	17
99	17
100	17

[0, 1, 7, 2, 5, 8, 16, 3, 11, 6, 14, 9, 9, 17, 17, 4, 12, 12, 20, 7, 7, 15, 15, 10, 23, 10, 23, 10, 18, 18, 31, 5, 18, 13, 13, 13, 13, 21, 26, 8, 21, 8, 21, 16, 16, 16, 29, 11, 16, 16, 24, 11, 11, 24, 24, 11, 24, 19, 24, 19, 19, 32, 32, 6, 19, 19, 27, 14, 14, 14, 27, 14, 27, 14, 14, 22, 22, 27, 27, 9, 22, 22, 22, 9, 9, 22, 22, 17, 22, 17, 30, 17, 17, 30, 30, 12, 30, 17, 17, 17]

cp's OEIS Frontend

A127885 a(n) = minimal number of steps to get from n to 1, where a step is x -> 3x+1 if x is odd, or x -> either x/2 or 3x+1 if x is even; or -1 if 1 is never reached.

Table of values

List of values

n	a(n)
1	0
2	1
3	7
4	2
5	5
6	8
7	16
8	3
9	11
10	6
11	14
12	9
13	9
14	17
15	17
16	4
17	12
18	12
19	20
20	7
21	7
22	15
23	15
24	10
25	23
26	10
27	23
28	10
29	18
30	18
31	31
32	5
33	18
34	13
35	13
36	13
37	13
38	21
39	26
40	8
41	21
42	8
43	21
44	16
45	16
46	16
47	29
48	11
49	16
50	16
51	24
52	11
53	11
54	24
55	24
56	11
57	24
58	19
59	24
60	19
61	19
62	32
63	32
64	6
65	19
66	19
67	27
68	14
69	14
70	14
71	27
72	14
73	27
74	14
75	14
76	22
77	22
78	27
79	27
80	9
81	22
82	22
83	22
84	9
85	9
86	22
87	22
88	17
89	22
90	17
91	30
92	17
93	17
94	30
95	30
96	12
97	30
98	17
99	17
100	17

n	a(n)
1	0
2	1
3	7
4	2
5	5
6	8
7	16
8	3
9	11
10	6
11	14
12	9
13	9
14	17
15	17
16	4
17	12
18	12
19	20
20	7
21	7
22	15
23	15
24	10
25	23
26	10
27	23
28	10
29	18
30	18
31	31
32	5
33	18
34	13
35	13
36	13
37	13
38	21
39	26
40	8
41	21
42	8
43	21
44	16
45	16
46	16
47	29
48	11
49	16
50	16
51	24
52	11
53	11
54	24
55	24
56	11
57	24
58	19
59	24
60	19
61	19
62	32
63	32
64	6
65	19
66	19
67	27
68	14
69	14
70	14
71	27
72	14
73	27
74	14
75	14
76	22
77	22
78	27
79	27
80	9
81	22
82	22
83	22
84	9
85	9
86	22
87	22
88	17
89	22
90	17
91	30
92	17
93	17
94	30
95	30
96	12
97	30
98	17
99	17
100	17

n	a(n)
1	0
2	1
3	7
4	2
5	5
6	8
7	16
8	3
9	11
10	6
11	14
12	9
13	9
14	17
15	17
16	4
17	12
18	12
19	20
20	7
21	7
22	15
23	15
24	10
25	23
26	10
27	23
28	10
29	18
30	18
31	31
32	5
33	18
34	13
35	13
36	13
37	13
38	21
39	26
40	8
41	21
42	8
43	21
44	16
45	16
46	16
47	29
48	11
49	16
50	16
51	24
52	11
53	11
54	24
55	24
56	11
57	24
58	19
59	24
60	19
61	19
62	32
63	32
64	6
65	19
66	19
67	27
68	14
69	14
70	14
71	27
72	14
73	27
74	14
75	14
76	22
77	22
78	27
79	27
80	9
81	22
82	22
83	22
84	9
85	9
86	22
87	22
88	17
89	22
90	17
91	30
92	17
93	17
94	30
95	30
96	12
97	30
98	17
99	17
100	17