A365048 - cp's OEIS frontend

A365048 a(n) is the number of steps required for the n-th odd prime number to reach 3 when iterating the following hailstone map: If P+1 == 0 (mod 6), then the next number = smallest prime >= P + (P-1)/2; otherwise the next number = largest prime <= (P+1)/2.

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

[0, 2, 1, 6, 2, 5, 2, 4, 4, 3, 3, 5, 3, 8, 5, 13, 4, 4, 7, 4, 4, 6, 12, 9, 6, 9, 6, 6, 14, 5, 8, 11, 5, 8, 5, 5, 5, 16, 13, 13, 13, 13, 10, 7, 10, 10, 7, 15, 15, 15, 12, 15, 15, 12, 12, 12, 9, 6, 12, 6, 12, 6, 17, 6, 14, 6, 17, 14, 14, 11, 11, 14, 14, 14, 8, 11, 11, 14, 11, 8, 11, 16]

cp's OEIS Frontend

A365048 a(n) is the number of steps required for the n-th odd prime number to reach 3 when iterating the following hailstone map: If P+1 == 0 (mod 6), then the next number = smallest prime >= P + (P-1)/2; otherwise the next number = largest prime <= (P+1)/2.

Table of values

List of values

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

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

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