A075997 - cp's OEIS frontend

A075997 a(n) = [n/2] - [n/3] + [n/4] - [n/5] + [n/6] - ..., where [n/k] = floor(n/k).

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

[0, 0, 1, 0, 2, 1, 2, 1, 4, 2, 3, 2, 5, 4, 5, 2, 6, 5, 6, 5, 8, 5, 6, 5, 10, 8, 9, 6, 9, 8, 9, 8, 13, 10, 11, 8, 12, 11, 12, 9, 14, 13, 14, 13, 16, 11, 12, 11, 18, 16, 17, 14, 17, 16, 17, 14, 19, 16, 17, 16, 21, 20, 21, 16, 22, 19, 20, 19, 22, 19, 20, 19, 26, 25, 26, 21, 24, 21, 22, 21]

cp's OEIS Frontend

A075997 a(n) = [n/2] - [n/3] + [n/4] - [n/5] + [n/6] - ..., where [n/k] = floor(n/k).

Table of values

List of values

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

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

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