A131187 - cp's OEIS frontend

A131187 a(n) = the number of positive integers < n that are neither a divisor of n nor a divisor of (n+1).

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

[0, 0, 0, 1, 1, 2, 3, 3, 4, 6, 5, 6, 9, 8, 8, 11, 11, 12, 13, 12, 15, 18, 15, 15, 20, 20, 19, 22, 21, 22, 25, 24, 27, 28, 24, 27, 33, 32, 29, 32, 33, 34, 37, 34, 37, 42, 37, 37, 42, 42, 43, 46, 45, 44, 45, 46, 51, 54, 47, 48, 57, 54, 52, 55, 55, 58, 61, 60, 59, 62, 59, 60, 69, 66]

cp's OEIS Frontend

A131187 a(n) = the number of positive integers < n that are neither a divisor of n nor a divisor of (n+1).

Table of values

List of values

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

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

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