A239328 - cp's OEIS frontend

A239328 Number of primes p < n with pi(p*n) - pi((p-1)n) prime, where pi(x) denotes the number of primes not exceeding x.

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

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

cp's OEIS Frontend

A239328 Number of primes p < n with pi(p*n) - pi((p-1)n) prime, where pi(x) denotes the number of primes not exceeding x.

Table of values

List of values

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

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

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