A243403 - cp's OEIS frontend

A243403 Number of primes p < n such that p*(n-p) is a primitive root modulo prime(n).

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

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

cp's OEIS Frontend

A243403 Number of primes p < n such that p*(n-p) 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	2
6	0
7	3
8	2
9	3
10	2
11	1
12	3
13	3
14	2
15	3
16	4
17	4
18	1
19	4
20	1
21	2
22	2
23	5
24	8
25	5
26	1
27	1
28	5
29	3
30	6
31	6
32	7
33	6
34	6
35	4
36	2
37	4
38	3
39	6
40	11
41	6
42	4
43	3
44	7
45	6
46	8
47	3
48	2
49	10
50	9
51	6
52	11
53	2
54	8
55	9
56	9
57	5
58	2
59	5
60	2
61	3
62	13
63	5
64	14
65	8
66	12
67	7
68	8
69	9
70	6
71	13
72	9
73	4
74	10
75	3
76	13
77	12
78	4
79	8
80	4

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

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