A088019 - cp's OEIS frontend

A088019 Number of twin primes between n and 2n (inclusive).

n	a(n)
1	0
2	1
3	2
4	2
5	2
6	2
7	3
8	2
9	3
10	4
11	4
12	3
13	3
14	2
15	3
16	4
17	4
18	3
19	3
20	2
21	3
22	4
23	4
24	4
25	4
26	4
27	4
28	4
29	4
30	4
31	5
32	4
33	4
34	4
35	4
36	5
37	6
38	6
39	6
40	6
41	6
42	5
43	5
44	4
45	4
46	4
47	4
48	4
49	4
50	4
51	5
52	6
53	6
54	7
55	8
56	8
57	8
58	8
59	8
60	7
61	7
62	6
63	6
64	6
65	6
66	6
67	6
68	6
69	7
70	8
71	8
72	7
73	7
74	6
75	7
76	8
77	8
78	8
79	8
80	8
81	8
82	8
83	8
84	8
85	8
86	8
87	8
88	8
89	8
90	9
91	10
92	10
93	10
94	10
95	10
96	11
97	12
98	12
99	13
100	14

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

cp's OEIS Frontend

A088019 Number of twin primes between n and 2n (inclusive).

Table of values

List of values

n	a(n)
1	0
2	1
3	2
4	2
5	2
6	2
7	3
8	2
9	3
10	4
11	4
12	3
13	3
14	2
15	3
16	4
17	4
18	3
19	3
20	2
21	3
22	4
23	4
24	4
25	4
26	4
27	4
28	4
29	4
30	4
31	5
32	4
33	4
34	4
35	4
36	5
37	6
38	6
39	6
40	6
41	6
42	5
43	5
44	4
45	4
46	4
47	4
48	4
49	4
50	4
51	5
52	6
53	6
54	7
55	8
56	8
57	8
58	8
59	8
60	7
61	7
62	6
63	6
64	6
65	6
66	6
67	6
68	6
69	7
70	8
71	8
72	7
73	7
74	6
75	7
76	8
77	8
78	8
79	8
80	8
81	8
82	8
83	8
84	8
85	8
86	8
87	8
88	8
89	8
90	9
91	10
92	10
93	10
94	10
95	10
96	11
97	12
98	12
99	13
100	14

n	a(n)
1	0
2	1
3	2
4	2
5	2
6	2
7	3
8	2
9	3
10	4
11	4
12	3
13	3
14	2
15	3
16	4
17	4
18	3
19	3
20	2
21	3
22	4
23	4
24	4
25	4
26	4
27	4
28	4
29	4
30	4
31	5
32	4
33	4
34	4
35	4
36	5
37	6
38	6
39	6
40	6
41	6
42	5
43	5
44	4
45	4
46	4
47	4
48	4
49	4
50	4
51	5
52	6
53	6
54	7
55	8
56	8
57	8
58	8
59	8
60	7
61	7
62	6
63	6
64	6
65	6
66	6
67	6
68	6
69	7
70	8
71	8
72	7
73	7
74	6
75	7
76	8
77	8
78	8
79	8
80	8
81	8
82	8
83	8
84	8
85	8
86	8
87	8
88	8
89	8
90	9
91	10
92	10
93	10
94	10
95	10
96	11
97	12
98	12
99	13
100	14

n	a(n)
1	0
2	1
3	2
4	2
5	2
6	2
7	3
8	2
9	3
10	4
11	4
12	3
13	3
14	2
15	3
16	4
17	4
18	3
19	3
20	2
21	3
22	4
23	4
24	4
25	4
26	4
27	4
28	4
29	4
30	4
31	5
32	4
33	4
34	4
35	4
36	5
37	6
38	6
39	6
40	6
41	6
42	5
43	5
44	4
45	4
46	4
47	4
48	4
49	4
50	4
51	5
52	6
53	6
54	7
55	8
56	8
57	8
58	8
59	8
60	7
61	7
62	6
63	6
64	6
65	6
66	6
67	6
68	6
69	7
70	8
71	8
72	7
73	7
74	6
75	7
76	8
77	8
78	8
79	8
80	8
81	8
82	8
83	8
84	8
85	8
86	8
87	8
88	8
89	8
90	9
91	10
92	10
93	10
94	10
95	10
96	11
97	12
98	12
99	13
100	14