A243847 - cp's OEIS frontend

A243847 a(n) = |{0 < k < n: prime(k) is a primitive root modulo prime(n) and also a primitive root modulo prime(2*n)}|.

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

[0, 0, 1, 1, 1, 1, 2, 2, 2, 1, 1, 2, 3, 1, 5, 2, 1, 1, 3, 5, 2, 3, 2, 3, 5, 4, 4, 7, 1, 5, 5, 7, 7, 6, 8, 6, 6, 5, 6, 3, 5, 4, 8, 6, 4, 5, 6, 6, 12, 8, 15, 17, 7, 10, 8, 11, 10, 8, 9, 10, 7, 18, 6, 15, 4, 9, 5, 10, 10, 8]

cp's OEIS Frontend

A243847 a(n) = |{0 < k < n: prime(k) is a primitive root modulo prime(n) and also a primitive root modulo prime(2*n)}|.

Table of values

List of values

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

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

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