A320028 - cp's OEIS frontend

A320028 a(n) is the first prime encountered when running the Collatz algorithm (halving and tripling steps) on the number n.

n	a(n)
2	2
3	3
4	2
5	5
6	3
7	7
8	2
9	7
10	5
11	11
12	3
13	13
14	7
15	23
16	2
17	17
18	7
19	19
20	5
21	2
22	11
23	23
24	3
25	19
26	13
27	41
28	7
29	29
30	23
31	31
32	2
33	19
34	17
35	53
36	7
37	37
38	19
39	59
40	5
41	41
42	2
43	43
44	11
45	17
46	23
47	47
48	3
49	37
50	19
51	29
52	13
53	53
54	41
55	83
56	7
57	43
58	29
59	59
60	23
61	61
62	31
63	137
64	2
65	37
66	19
67	67
68	17
69	13
70	53
71	71
72	7
73	73
74	37
75	113
76	19
77	29
78	59
79	79
80	5
81	61
82	41
83	83
84	2
85	2
86	43
87	131

[2, 3, 2, 5, 3, 7, 2, 7, 5, 11, 3, 13, 7, 23, 2, 17, 7, 19, 5, 2, 11, 23, 3, 19, 13, 41, 7, 29, 23, 31, 2, 19, 17, 53, 7, 37, 19, 59, 5, 41, 2, 43, 11, 17, 23, 47, 3, 37, 19, 29, 13, 53, 41, 83, 7, 43, 29, 59, 23, 61, 31, 137, 2, 37, 19, 67, 17, 13, 53, 71, 7, 73, 37, 113, 19, 29, 59, 79, 5, 61, 41, 83, 2, 2, 43, 131]

cp's OEIS Frontend

A320028 a(n) is the first prime encountered when running the Collatz algorithm (halving and tripling steps) on the number n.

Table of values

List of values

n	a(n)
2	2
3	3
4	2
5	5
6	3
7	7
8	2
9	7
10	5
11	11
12	3
13	13
14	7
15	23
16	2
17	17
18	7
19	19
20	5
21	2
22	11
23	23
24	3
25	19
26	13
27	41
28	7
29	29
30	23
31	31
32	2
33	19
34	17
35	53
36	7
37	37
38	19
39	59
40	5
41	41
42	2
43	43
44	11
45	17
46	23
47	47
48	3
49	37
50	19
51	29
52	13
53	53
54	41
55	83
56	7
57	43
58	29
59	59
60	23
61	61
62	31
63	137
64	2
65	37
66	19
67	67
68	17
69	13
70	53
71	71
72	7
73	73
74	37
75	113
76	19
77	29
78	59
79	79
80	5
81	61
82	41
83	83
84	2
85	2
86	43
87	131

n	a(n)
2	2
3	3
4	2
5	5
6	3
7	7
8	2
9	7
10	5
11	11
12	3
13	13
14	7
15	23
16	2
17	17
18	7
19	19
20	5
21	2
22	11
23	23
24	3
25	19
26	13
27	41
28	7
29	29
30	23
31	31
32	2
33	19
34	17
35	53
36	7
37	37
38	19
39	59
40	5
41	41
42	2
43	43
44	11
45	17
46	23
47	47
48	3
49	37
50	19
51	29
52	13
53	53
54	41
55	83
56	7
57	43
58	29
59	59
60	23
61	61
62	31
63	137
64	2
65	37
66	19
67	67
68	17
69	13
70	53
71	71
72	7
73	73
74	37
75	113
76	19
77	29
78	59
79	79
80	5
81	61
82	41
83	83
84	2
85	2
86	43
87	131

n	a(n)
2	2
3	3
4	2
5	5
6	3
7	7
8	2
9	7
10	5
11	11
12	3
13	13
14	7
15	23
16	2
17	17
18	7
19	19
20	5
21	2
22	11
23	23
24	3
25	19
26	13
27	41
28	7
29	29
30	23
31	31
32	2
33	19
34	17
35	53
36	7
37	37
38	19
39	59
40	5
41	41
42	2
43	43
44	11
45	17
46	23
47	47
48	3
49	37
50	19
51	29
52	13
53	53
54	41
55	83
56	7
57	43
58	29
59	59
60	23
61	61
62	31
63	137
64	2
65	37
66	19
67	67
68	17
69	13
70	53
71	71
72	7
73	73
74	37
75	113
76	19
77	29
78	59
79	79
80	5
81	61
82	41
83	83
84	2
85	2
86	43
87	131