A239330 - cp's OEIS frontend

A239330 Number of odd primes p <= n with pi(n(p+1)/2) - pi(n(p-1)/2) 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	2
8	3
9	3
10	2
11	4
12	2
13	5
14	3
15	3
16	4
17	1
18	3
19	4
20	4
21	5
22	4
23	4
24	4
25	4
26	3
27	3
28	5
29	5
30	5
31	3
32	6
33	8
34	5
35	5
36	3
37	5
38	6
39	4
40	4
41	7
42	6
43	4
44	4
45	3
46	5
47	3
48	4
49	3
50	5
51	4
52	4
53	3
54	3
55	4
56	2
57	4
58	2
59	4
60	4
61	3
62	4
63	9
64	3
65	7
66	4
67	6
68	4
69	5
70	5
71	7
72	4
73	9
74	9
75	7
76	7
77	11
78	7
79	8
80	8

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

cp's OEIS Frontend

A239330 Number of odd primes p <= n with pi(n(p+1)/2) - pi(n(p-1)/2) 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	2
8	3
9	3
10	2
11	4
12	2
13	5
14	3
15	3
16	4
17	1
18	3
19	4
20	4
21	5
22	4
23	4
24	4
25	4
26	3
27	3
28	5
29	5
30	5
31	3
32	6
33	8
34	5
35	5
36	3
37	5
38	6
39	4
40	4
41	7
42	6
43	4
44	4
45	3
46	5
47	3
48	4
49	3
50	5
51	4
52	4
53	3
54	3
55	4
56	2
57	4
58	2
59	4
60	4
61	3
62	4
63	9
64	3
65	7
66	4
67	6
68	4
69	5
70	5
71	7
72	4
73	9
74	9
75	7
76	7
77	11
78	7
79	8
80	8

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

cp's OEIS Frontend

A239330 Number of odd primes p <= n with pi(n*(p+1)/2) - pi(n*(p-1)/2) prime, where pi(x) denotes the number of primes not exceeding x.

Table of values

List of values

A239330 Number of odd primes p <= n with pi(n(p+1)/2) - pi(n(p-1)/2) 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	2
8	3
9	3
10	2
11	4
12	2
13	5
14	3
15	3
16	4
17	1
18	3
19	4
20	4
21	5
22	4
23	4
24	4
25	4
26	3
27	3
28	5
29	5
30	5
31	3
32	6
33	8
34	5
35	5
36	3
37	5
38	6
39	4
40	4
41	7
42	6
43	4
44	4
45	3
46	5
47	3
48	4
49	3
50	5
51	4
52	4
53	3
54	3
55	4
56	2
57	4
58	2
59	4
60	4
61	3
62	4
63	9
64	3
65	7
66	4
67	6
68	4
69	5
70	5
71	7
72	4
73	9
74	9
75	7
76	7
77	11
78	7
79	8
80	8