A242222 - cp's OEIS frontend

A242222 Number of primes p <= (prime(n)+1)/2 such that the harmonic number H(p-1) = sum_{0 is a primitive root modulo prime(n), or 0 if such a prime p does not exist.

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

[0, 0, 0, 1, 1, 1, 3, 1, 1, 1, 2, 3, 4, 4, 5, 6, 3, 2, 3, 2, 3, 2, 6, 6, 4, 6, 4, 8, 7, 9, 5, 7, 11, 5, 11, 5, 6, 6, 11, 8, 12, 7, 8, 9, 8, 11, 7, 13, 18, 8, 18, 14, 8, 9, 14, 18, 17, 7, 14, 11, 9, 19, 10, 12, 7, 21, 5, 15, 19, 15]

cp's OEIS Frontend

A242222 Number of primes p <= (prime(n)+1)/2 such that the harmonic number H(p-1) = sum_{0 is a primitive root modulo prime(n), or 0 if such a prime p does not exist.

Table of values

List of values

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

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

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