A382117 - cp's OEIS frontend

A382117 a(n) = sum (-1)^(((x - 1)*(y - 1))/4), where x and y are coprime positive integers, equidistant from n, such that x <= y.

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

[1, 1, 1, 2, 0, 2, 1, 4, 1, 4, 1, 4, 0, 6, 0, 8, 0, 6, 1, 8, 2, 10, 1, 8, 0, 12, 1, 12, 0, 8, 1, 16, 2, 16, 0, 12, 0, 18, 0, 16, 0, 12, 1, 20, 0, 22, 1, 16, 1, 20, 0, 24, 0, 18, 0, 24, 2, 28, 1, 16, 0, 30, 2, 32, 0, 20, 1, 32, 2, 24, 1, 24, 0, 36, 0, 36, 2, 24]

cp's OEIS Frontend

A382117 a(n) = sum (-1)^(((x - 1)*(y - 1))/4), where x and y are coprime positive integers, equidistant from n, such that x <= y.

Table of values

List of values

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

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

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