A373923 - cp's OEIS frontend

A373923 a(n) = Sum_{d|n} (-1)^pi(d).

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

[1, 0, 2, 1, 0, 0, 2, 2, 3, 0, 0, 0, 2, 2, 2, 3, 0, 0, 2, 2, 4, 0, 0, 0, -1, 0, 2, 2, 2, 2, 0, 2, 0, -2, 0, -1, 2, 2, 4, 4, 0, 2, 2, 2, 4, 0, 0, 0, 1, -2, 0, 0, 2, 0, 0, 4, 4, 2, 0, 2, 2, 0, 6, 3, 2, 0, 0, -2, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 2, 6, 3, 0, 0, 0, -2, 0, 2, 2]

cp's OEIS Frontend

A373923 a(n) = Sum_{d|n} (-1)^pi(d).

Table of values

List of values

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

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

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