A304576 - cp's OEIS frontend

A304576 a(n) = Sum_{k < n, k squarefree and relatively prime to n} (-1)^(k-1).

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

[1, 1, 0, 2, 1, 2, 1, 4, 2, 3, 1, 4, 2, 5, 2, 7, 3, 6, 4, 7, 4, 9, 5, 8, 5, 10, 3, 9, 5, 8, 5, 13, 5, 13, 5, 11, 7, 15, 5, 14, 8, 11, 8, 17, 6, 18, 8, 15, 8, 17, 7, 19, 10, 16, 9, 20, 9, 23, 12, 15, 13, 25, 8, 26, 10, 18, 13, 26, 11, 22, 14, 22, 15, 30, 9, 29]

cp's OEIS Frontend

A304576 a(n) = Sum_{k < n, k squarefree and relatively prime to n} (-1)^(k-1).

Table of values

List of values

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

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

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