A076545 - cp's OEIS frontend

A076545 a(n) = Sum_{k=1..n} (mu(k) + sqf(k)) where mu(k) is Moebius function, sqf(k)=1 if k is squarefree and sqf(k)=-1 otherwise.

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

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

cp's OEIS Frontend

A076545 a(n) = Sum_{k=1..n} (mu(k) + sqf(k)) where mu(k) is Moebius function, sqf(k)=1 if k is squarefree and sqf(k)=-1 otherwise.

Table of values

List of values

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

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

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