A181834 - cp's OEIS frontend

A181834 The number of primes <= n that are strongly prime to n.

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

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

cp's OEIS Frontend

A181834 The number of primes <= n that are strongly prime to n.

Table of values

List of values

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

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

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