A268731 - cp's OEIS frontend

A268731 Period of the decimal expansion of 1/h(n) where h(n) is the length of the finite sequence {n, f(n), f(f(n)),...,1} in the Collatz (or 3n + 1) problem.

n	a(n)
2	1
3	6
4	1
5	1
6	1
7	1
8	1
9	18
10	1
11	6
12	1
13	1
14	16
15	16
16	1
17	1
18	1
19	1
20	6
21	6
22	1
23	1
24	1
25	22
26	1
27	3
28	1
29	1
30	1
31	13
32	1
33	6
34	6
35	6
36	6
37	6
38	6
39	16
40	1
41	108
42	1
43	28
44	1
45	1
46	1
47	6
48	2
49	1
50	1
51	1
52	2
53	2
54	6
55	6
56	18
57	1
58	18
59	1
60	18
61	18
62	53
63	53
64	1
65	3
66	3
67	3
68	6
69	6
70	6
71	16
72	2
73	22
74	2
75	6
76	2
77	2
78	6
79	6
80	1
81	2
82	2
83	2

[1, 6, 1, 1, 1, 1, 1, 18, 1, 6, 1, 1, 16, 16, 1, 1, 1, 1, 6, 6, 1, 1, 1, 22, 1, 3, 1, 1, 1, 13, 1, 6, 6, 6, 6, 6, 6, 16, 1, 108, 1, 28, 1, 1, 1, 6, 2, 1, 1, 1, 2, 2, 6, 6, 18, 1, 18, 1, 18, 18, 53, 53, 1, 3, 3, 3, 6, 6, 6, 16, 2, 22, 2, 6, 2, 2, 6, 6, 1, 2, 2, 2]

cp's OEIS Frontend

A268731 Period of the decimal expansion of 1/h(n) where h(n) is the length of the finite sequence {n, f(n), f(f(n)),...,1} in the Collatz (or 3n + 1) problem.

Table of values

List of values

n	a(n)
2	1
3	6
4	1
5	1
6	1
7	1
8	1
9	18
10	1
11	6
12	1
13	1
14	16
15	16
16	1
17	1
18	1
19	1
20	6
21	6
22	1
23	1
24	1
25	22
26	1
27	3
28	1
29	1
30	1
31	13
32	1
33	6
34	6
35	6
36	6
37	6
38	6
39	16
40	1
41	108
42	1
43	28
44	1
45	1
46	1
47	6
48	2
49	1
50	1
51	1
52	2
53	2
54	6
55	6
56	18
57	1
58	18
59	1
60	18
61	18
62	53
63	53
64	1
65	3
66	3
67	3
68	6
69	6
70	6
71	16
72	2
73	22
74	2
75	6
76	2
77	2
78	6
79	6
80	1
81	2
82	2
83	2

n	a(n)
2	1
3	6
4	1
5	1
6	1
7	1
8	1
9	18
10	1
11	6
12	1
13	1
14	16
15	16
16	1
17	1
18	1
19	1
20	6
21	6
22	1
23	1
24	1
25	22
26	1
27	3
28	1
29	1
30	1
31	13
32	1
33	6
34	6
35	6
36	6
37	6
38	6
39	16
40	1
41	108
42	1
43	28
44	1
45	1
46	1
47	6
48	2
49	1
50	1
51	1
52	2
53	2
54	6
55	6
56	18
57	1
58	18
59	1
60	18
61	18
62	53
63	53
64	1
65	3
66	3
67	3
68	6
69	6
70	6
71	16
72	2
73	22
74	2
75	6
76	2
77	2
78	6
79	6
80	1
81	2
82	2
83	2

n	a(n)
2	1
3	6
4	1
5	1
6	1
7	1
8	1
9	18
10	1
11	6
12	1
13	1
14	16
15	16
16	1
17	1
18	1
19	1
20	6
21	6
22	1
23	1
24	1
25	22
26	1
27	3
28	1
29	1
30	1
31	13
32	1
33	6
34	6
35	6
36	6
37	6
38	6
39	16
40	1
41	108
42	1
43	28
44	1
45	1
46	1
47	6
48	2
49	1
50	1
51	1
52	2
53	2
54	6
55	6
56	18
57	1
58	18
59	1
60	18
61	18
62	53
63	53
64	1
65	3
66	3
67	3
68	6
69	6
70	6
71	16
72	2
73	22
74	2
75	6
76	2
77	2
78	6
79	6
80	1
81	2
82	2
83	2