A048865 - cp's OEIS frontend

A048865 a(n) is the number of primes in the reduced residue system mod n.

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

[0, 0, 1, 1, 2, 1, 3, 3, 3, 2, 4, 3, 5, 4, 4, 5, 6, 5, 7, 6, 6, 6, 8, 7, 8, 7, 8, 7, 9, 7, 10, 10, 9, 9, 9, 9, 11, 10, 10, 10, 12, 10, 13, 12, 12, 12, 14, 13, 14, 13, 13, 13, 15, 14, 14, 14, 14, 14, 16, 14, 17, 16, 16, 17, 16, 15, 18, 17, 17, 16, 19, 18, 20, 19, 19, 19, 19, 18, 21, 20, 21]

cp's OEIS Frontend

A048865 a(n) is the number of primes in the reduced residue system mod n.

Table of values

List of values

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

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

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