A072531 - cp's OEIS frontend

A072531 Number of primes p < n such that n divided by p leaves a 1 or a composite (nonzero) remainder.

n	a(n)
1	0
2	0
3	1
4	1
5	1
6	1
7	2
8	1
9	2
10	1
11	3
12	1
13	3
14	2
15	3
16	2
17	3
18	2
19	5
20	3
21	5
22	3
23	5
24	2
25	6
26	3
27	6
28	3
29	6
30	3
31	7
32	6
33	5
34	6
35	7
36	3
37	7
38	5
39	8
40	4
41	8
42	4
43	10
44	6
45	8
46	7
47	9
48	6
49	10
50	7
51	9
52	8
53	11
54	6
55	11
56	9
57	10
58	7
59	11
60	5
61	14
62	9
63	11
64	9
65	11
66	8
67	15
68	9
69	13
70	8
71	14
72	8
73	14
74	12
75	14
76	11
77	15
78	9
79	15
80	11
81	14
82	12
83	18
84	10
85	16
86	14
87	15
88	13
89	16
90	9

[0, 0, 1, 1, 1, 1, 2, 1, 2, 1, 3, 1, 3, 2, 3, 2, 3, 2, 5, 3, 5, 3, 5, 2, 6, 3, 6, 3, 6, 3, 7, 6, 5, 6, 7, 3, 7, 5, 8, 4, 8, 4, 10, 6, 8, 7, 9, 6, 10, 7, 9, 8, 11, 6, 11, 9, 10, 7, 11, 5, 14, 9, 11, 9, 11, 8, 15, 9, 13, 8, 14, 8, 14, 12, 14, 11, 15, 9, 15, 11, 14, 12, 18, 10, 16, 14, 15, 13, 16, 9]

cp's OEIS Frontend

A072531 Number of primes p < n such that n divided by p leaves a 1 or a composite (nonzero) remainder.

Table of values

List of values

n	a(n)
1	0
2	0
3	1
4	1
5	1
6	1
7	2
8	1
9	2
10	1
11	3
12	1
13	3
14	2
15	3
16	2
17	3
18	2
19	5
20	3
21	5
22	3
23	5
24	2
25	6
26	3
27	6
28	3
29	6
30	3
31	7
32	6
33	5
34	6
35	7
36	3
37	7
38	5
39	8
40	4
41	8
42	4
43	10
44	6
45	8
46	7
47	9
48	6
49	10
50	7
51	9
52	8
53	11
54	6
55	11
56	9
57	10
58	7
59	11
60	5
61	14
62	9
63	11
64	9
65	11
66	8
67	15
68	9
69	13
70	8
71	14
72	8
73	14
74	12
75	14
76	11
77	15
78	9
79	15
80	11
81	14
82	12
83	18
84	10
85	16
86	14
87	15
88	13
89	16
90	9

n	a(n)
1	0
2	0
3	1
4	1
5	1
6	1
7	2
8	1
9	2
10	1
11	3
12	1
13	3
14	2
15	3
16	2
17	3
18	2
19	5
20	3
21	5
22	3
23	5
24	2
25	6
26	3
27	6
28	3
29	6
30	3
31	7
32	6
33	5
34	6
35	7
36	3
37	7
38	5
39	8
40	4
41	8
42	4
43	10
44	6
45	8
46	7
47	9
48	6
49	10
50	7
51	9
52	8
53	11
54	6
55	11
56	9
57	10
58	7
59	11
60	5
61	14
62	9
63	11
64	9
65	11
66	8
67	15
68	9
69	13
70	8
71	14
72	8
73	14
74	12
75	14
76	11
77	15
78	9
79	15
80	11
81	14
82	12
83	18
84	10
85	16
86	14
87	15
88	13
89	16
90	9

n	a(n)
1	0
2	0
3	1
4	1
5	1
6	1
7	2
8	1
9	2
10	1
11	3
12	1
13	3
14	2
15	3
16	2
17	3
18	2
19	5
20	3
21	5
22	3
23	5
24	2
25	6
26	3
27	6
28	3
29	6
30	3
31	7
32	6
33	5
34	6
35	7
36	3
37	7
38	5
39	8
40	4
41	8
42	4
43	10
44	6
45	8
46	7
47	9
48	6
49	10
50	7
51	9
52	8
53	11
54	6
55	11
56	9
57	10
58	7
59	11
60	5
61	14
62	9
63	11
64	9
65	11
66	8
67	15
68	9
69	13
70	8
71	14
72	8
73	14
74	12
75	14
76	11
77	15
78	9
79	15
80	11
81	14
82	12
83	18
84	10
85	16
86	14
87	15
88	13
89	16
90	9