A033270 - cp's OEIS frontend

A033270 Number of odd primes <= n.

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

[0, 0, 1, 1, 2, 2, 3, 3, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 9, 9, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 16, 16, 17, 17, 17, 17]

cp's OEIS Frontend

A033270 Number of odd primes <= n.

Table of values

List of values

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

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

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