A236966 - cp's OEIS frontend

A236966 Number of primes p < prime(n)/2 such that 2^p - 1 is a primitive root modulo prime(n).

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

[0, 0, 1, 1, 1, 1, 3, 2, 1, 3, 2, 1, 2, 2, 5, 6, 3, 4, 3, 5, 4, 5, 7, 9, 3, 5, 2, 10, 7, 7, 7, 7, 9, 5, 10, 4, 5, 7, 12, 11, 14, 6, 7, 5, 10, 9, 8, 5, 12, 15, 14, 8, 12, 11, 16, 12, 16, 9, 12, 10, 10, 14, 15, 10, 12, 14, 9, 10, 21, 9, 22, 21, 11, 9, 18, 24, 20, 17, 17, 16]

cp's OEIS Frontend

A236966 Number of primes p < prime(n)/2 such that 2^p - 1 is a primitive root modulo prime(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	2
9	1
10	3
11	2
12	1
13	2
14	2
15	5
16	6
17	3
18	4
19	3
20	5
21	4
22	5
23	7
24	9
25	3
26	5
27	2
28	10
29	7
30	7
31	7
32	7
33	9
34	5
35	10
36	4
37	5
38	7
39	12
40	11
41	14
42	6
43	7
44	5
45	10
46	9
47	8
48	5
49	12
50	15
51	14
52	8
53	12
54	11
55	16
56	12
57	16
58	9
59	12
60	10
61	10
62	14
63	15
64	10
65	12
66	14
67	9
68	10
69	21
70	9
71	22
72	21
73	11
74	9
75	18
76	24
77	20
78	17
79	17
80	16

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

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