A123565 - cp's OEIS frontend

A123565 a(n) is the number of positive integers k which are <= n and where k, k-1 and k+1 are each coprime to n.

n	a(n)
1	1
2	0
3	0
4	0
5	2
6	0
7	4
8	0
9	0
10	0
11	8
12	0
13	10
14	0
15	0
16	0
17	14
18	0
19	16
20	0
21	0
22	0
23	20
24	0
25	10
26	0
27	0
28	0
29	26
30	0
31	28
32	0
33	0
34	0
35	8
36	0
37	34
38	0
39	0
40	0
41	38
42	0
43	40
44	0
45	0
46	0
47	44
48	0
49	28
50	0
51	0
52	0
53	50
54	0
55	16
56	0
57	0
58	0
59	56
60	0
61	58
62	0
63	0
64	0
65	20
66	0
67	64
68	0
69	0
70	0
71	68
72	0
73	70
74	0
75	0
76	0
77	32
78	0
79	76
80	0
81	0
82	0
83	80
84	0
85	28
86	0
87	0
88	0
89	86
90	0
91	40
92	0
93	0

[1, 0, 0, 0, 2, 0, 4, 0, 0, 0, 8, 0, 10, 0, 0, 0, 14, 0, 16, 0, 0, 0, 20, 0, 10, 0, 0, 0, 26, 0, 28, 0, 0, 0, 8, 0, 34, 0, 0, 0, 38, 0, 40, 0, 0, 0, 44, 0, 28, 0, 0, 0, 50, 0, 16, 0, 0, 0, 56, 0, 58, 0, 0, 0, 20, 0, 64, 0, 0, 0, 68, 0, 70, 0, 0, 0, 32, 0, 76, 0, 0, 0, 80, 0, 28, 0, 0, 0, 86, 0, 40, 0, 0]

cp's OEIS Frontend

A123565 a(n) is the number of positive integers k which are <= n and where k, k-1 and k+1 are each coprime to n.

Table of values

List of values

n	a(n)
1	1
2	0
3	0
4	0
5	2
6	0
7	4
8	0
9	0
10	0
11	8
12	0
13	10
14	0
15	0
16	0
17	14
18	0
19	16
20	0
21	0
22	0
23	20
24	0
25	10
26	0
27	0
28	0
29	26
30	0
31	28
32	0
33	0
34	0
35	8
36	0
37	34
38	0
39	0
40	0
41	38
42	0
43	40
44	0
45	0
46	0
47	44
48	0
49	28
50	0
51	0
52	0
53	50
54	0
55	16
56	0
57	0
58	0
59	56
60	0
61	58
62	0
63	0
64	0
65	20
66	0
67	64
68	0
69	0
70	0
71	68
72	0
73	70
74	0
75	0
76	0
77	32
78	0
79	76
80	0
81	0
82	0
83	80
84	0
85	28
86	0
87	0
88	0
89	86
90	0
91	40
92	0
93	0

n	a(n)
1	1
2	0
3	0
4	0
5	2
6	0
7	4
8	0
9	0
10	0
11	8
12	0
13	10
14	0
15	0
16	0
17	14
18	0
19	16
20	0
21	0
22	0
23	20
24	0
25	10
26	0
27	0
28	0
29	26
30	0
31	28
32	0
33	0
34	0
35	8
36	0
37	34
38	0
39	0
40	0
41	38
42	0
43	40
44	0
45	0
46	0
47	44
48	0
49	28
50	0
51	0
52	0
53	50
54	0
55	16
56	0
57	0
58	0
59	56
60	0
61	58
62	0
63	0
64	0
65	20
66	0
67	64
68	0
69	0
70	0
71	68
72	0
73	70
74	0
75	0
76	0
77	32
78	0
79	76
80	0
81	0
82	0
83	80
84	0
85	28
86	0
87	0
88	0
89	86
90	0
91	40
92	0
93	0

n	a(n)
1	1
2	0
3	0
4	0
5	2
6	0
7	4
8	0
9	0
10	0
11	8
12	0
13	10
14	0
15	0
16	0
17	14
18	0
19	16
20	0
21	0
22	0
23	20
24	0
25	10
26	0
27	0
28	0
29	26
30	0
31	28
32	0
33	0
34	0
35	8
36	0
37	34
38	0
39	0
40	0
41	38
42	0
43	40
44	0
45	0
46	0
47	44
48	0
49	28
50	0
51	0
52	0
53	50
54	0
55	16
56	0
57	0
58	0
59	56
60	0
61	58
62	0
63	0
64	0
65	20
66	0
67	64
68	0
69	0
70	0
71	68
72	0
73	70
74	0
75	0
76	0
77	32
78	0
79	76
80	0
81	0
82	0
83	80
84	0
85	28
86	0
87	0
88	0
89	86
90	0
91	40
92	0
93	0