A224989 - cp's OEIS frontend

A224989 Let p = prime(n). a(n) = number of primes q less than p, such that both p-q+1 and p-q-1 are primes.

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

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

cp's OEIS Frontend

A224989 Let p = prime(n). a(n) = number of primes q less than p, such that both p-q+1 and p-q-1 are primes.

Table of values

List of values

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

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

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