A101909 - cp's OEIS frontend

A101909 Number of primes between 2n and 4n.

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

[1, 2, 2, 2, 4, 4, 3, 5, 4, 4, 6, 6, 6, 7, 7, 7, 8, 9, 9, 10, 10, 9, 10, 9, 10, 12, 12, 13, 14, 13, 12, 13, 14, 13, 15, 14, 13, 15, 15, 15, 16, 16, 16, 17, 17, 18, 18, 19, 19, 21, 20, 19, 20, 19, 18, 19, 19, 20, 21, 22, 23, 23, 24, 23, 24, 24, 24, 26, 25, 25, 27, 27, 27, 28, 27, 26]

cp's OEIS Frontend

A101909 Number of primes between 2n and 4n.

Table of values

List of values

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

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

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