A082650 - cp's OEIS frontend

A082650 Number of primes < n of form 1+k*spf(n), where spf(n) is the smallest prime factor of n (A020639).

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

[0, 0, 0, 1, 0, 2, 0, 3, 1, 3, 0, 4, 0, 5, 2, 5, 0, 6, 0, 7, 3, 7, 0, 8, 1, 8, 3, 8, 0, 9, 0, 10, 4, 10, 2, 10, 0, 11, 5, 11, 0, 12, 0, 13, 6, 13, 0, 14, 2, 14, 6, 14, 0, 15, 3, 15, 6, 15, 0, 16, 0, 17, 7, 17, 4, 17, 0, 18, 8, 18, 0, 19, 0, 20, 9, 20, 3, 20, 0, 21, 10, 21, 0, 22, 5, 22, 10, 22, 0]

cp's OEIS Frontend

A082650 Number of primes < n of form 1+k*spf(n), where spf(n) is the smallest prime factor of n (A020639).

Table of values

List of values

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

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

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