A039642 - cp's OEIS frontend

A039642 Number of steps to fixed point of "k -> k/2 or (k-1)/2 until result is prime", starting with prime(n)-1.

n	a(n)
1	1
2	1
3	2
4	2
5	2
6	3
7	4
8	4
9	2
10	3
11	3
12	5
13	4
14	4
15	2
16	3
17	2
18	4
19	6
20	3
21	6
22	3
23	2
24	4
25	6
26	6
27	6
28	2
29	4
30	5
31	3
32	7
33	4
34	4
35	3
36	3
37	4
38	6
39	2
40	3
41	2
42	5
43	3
44	7
45	7
46	7
47	5
48	5
49	2
50	6
51	4
52	3
53	6
54	4
55	8
56	2
57	3
58	3
59	5
60	5
61	5
62	3
63	5
64	5
65	5
66	3
67	4
68	7
69	2
70	4
71	6
72	2
73	6
74	5
75	4
76	2
77	3
78	8
79	8
80	8
81	6
82	6
83	3
84	6
85	3
86	6
87	7
88	7
89	7
90	7
91	2
92	2
93	7
94	4
95	5
96	2
97	3
98	9
99	9
100	4
101	6
102	3

[1, 1, 2, 2, 2, 3, 4, 4, 2, 3, 3, 5, 4, 4, 2, 3, 2, 4, 6, 3, 6, 3, 2, 4, 6, 6, 6, 2, 4, 5, 3, 7, 4, 4, 3, 3, 4, 6, 2, 3, 2, 5, 3, 7, 7, 7, 5, 5, 2, 6, 4, 3, 6, 4, 8, 2, 3, 3, 5, 5, 5, 3, 5, 5, 5, 3, 4, 7, 2, 4, 6, 2, 6, 5, 4, 2, 3, 8, 8, 8, 6, 6, 3, 6, 3, 6, 7, 7, 7, 7, 2, 2, 7, 4, 5, 2, 3, 9, 9, 4, 6, 3]

cp's OEIS Frontend

A039642 Number of steps to fixed point of "k -> k/2 or (k-1)/2 until result is prime", starting with prime(n)-1.

Table of values

List of values

n	a(n)
1	1
2	1
3	2
4	2
5	2
6	3
7	4
8	4
9	2
10	3
11	3
12	5
13	4
14	4
15	2
16	3
17	2
18	4
19	6
20	3
21	6
22	3
23	2
24	4
25	6
26	6
27	6
28	2
29	4
30	5
31	3
32	7
33	4
34	4
35	3
36	3
37	4
38	6
39	2
40	3
41	2
42	5
43	3
44	7
45	7
46	7
47	5
48	5
49	2
50	6
51	4
52	3
53	6
54	4
55	8
56	2
57	3
58	3
59	5
60	5
61	5
62	3
63	5
64	5
65	5
66	3
67	4
68	7
69	2
70	4
71	6
72	2
73	6
74	5
75	4
76	2
77	3
78	8
79	8
80	8
81	6
82	6
83	3
84	6
85	3
86	6
87	7
88	7
89	7
90	7
91	2
92	2
93	7
94	4
95	5
96	2
97	3
98	9
99	9
100	4
101	6
102	3

n	a(n)
1	1
2	1
3	2
4	2
5	2
6	3
7	4
8	4
9	2
10	3
11	3
12	5
13	4
14	4
15	2
16	3
17	2
18	4
19	6
20	3
21	6
22	3
23	2
24	4
25	6
26	6
27	6
28	2
29	4
30	5
31	3
32	7
33	4
34	4
35	3
36	3
37	4
38	6
39	2
40	3
41	2
42	5
43	3
44	7
45	7
46	7
47	5
48	5
49	2
50	6
51	4
52	3
53	6
54	4
55	8
56	2
57	3
58	3
59	5
60	5
61	5
62	3
63	5
64	5
65	5
66	3
67	4
68	7
69	2
70	4
71	6
72	2
73	6
74	5
75	4
76	2
77	3
78	8
79	8
80	8
81	6
82	6
83	3
84	6
85	3
86	6
87	7
88	7
89	7
90	7
91	2
92	2
93	7
94	4
95	5
96	2
97	3
98	9
99	9
100	4
101	6
102	3

n	a(n)
1	1
2	1
3	2
4	2
5	2
6	3
7	4
8	4
9	2
10	3
11	3
12	5
13	4
14	4
15	2
16	3
17	2
18	4
19	6
20	3
21	6
22	3
23	2
24	4
25	6
26	6
27	6
28	2
29	4
30	5
31	3
32	7
33	4
34	4
35	3
36	3
37	4
38	6
39	2
40	3
41	2
42	5
43	3
44	7
45	7
46	7
47	5
48	5
49	2
50	6
51	4
52	3
53	6
54	4
55	8
56	2
57	3
58	3
59	5
60	5
61	5
62	3
63	5
64	5
65	5
66	3
67	4
68	7
69	2
70	4
71	6
72	2
73	6
74	5
75	4
76	2
77	3
78	8
79	8
80	8
81	6
82	6
83	3
84	6
85	3
86	6
87	7
88	7
89	7
90	7
91	2
92	2
93	7
94	4
95	5
96	2
97	3
98	9
99	9
100	4
101	6
102	3