A291615 - cp's OEIS frontend

A291615 Number of primes p < prime(n) such that p is a primitive root modulo prime(n) and also a primitive root modulo prime(p).

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

[0, 1, 2, 1, 2, 3, 3, 3, 2, 3, 3, 2, 3, 1, 3, 3, 3, 2, 5, 3, 2, 2, 4, 5, 5, 5, 2, 3, 3, 3, 4, 2, 6, 3, 11, 4, 3, 8, 9, 8, 10, 7, 6, 3, 9, 6, 6, 6, 11, 10, 11, 9, 9, 9, 12, 11, 13, 3, 6, 10, 7, 15, 5, 6, 7, 13, 7, 8, 14, 10, 13, 19, 12, 14, 11, 18, 15, 11, 15, 8]

cp's OEIS Frontend

A291615 Number of primes p < prime(n) such that p is a primitive root modulo prime(n) and also a primitive root modulo prime(p).

Table of values

List of values

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

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

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