A213181 - cp's OEIS frontend

A213181 Number of chains of even numbers of length 2 or more in the Collatz (3x+1) trajectory of n.

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

[0, 0, 1, 1, 1, 1, 3, 1, 4, 1, 3, 2, 2, 3, 2, 1, 3, 4, 4, 2, 1, 3, 2, 2, 5, 2, 17, 4, 4, 2, 16, 1, 6, 3, 2, 5, 4, 4, 6, 2, 17, 1, 6, 4, 4, 2, 16, 2, 5, 5, 5, 3, 2, 17, 17, 4, 7, 4, 6, 3, 3, 16, 15, 1, 6, 6, 5, 4, 3, 2, 16, 5, 18, 4, 2, 5, 5, 6, 6, 2, 4, 17, 17]

cp's OEIS Frontend

A213181 Number of chains of even numbers of length 2 or more in the Collatz (3x+1) trajectory of n.

Table of values

List of values

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

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

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