A156876 - cp's OEIS frontend

A156876 Number of primes <= n that are safe primes or Sophie Germain primes.

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

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

cp's OEIS Frontend

A156876 Number of primes <= n that are safe primes or Sophie Germain primes.

Table of values

List of values

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

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

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