A303691 - cp's OEIS frontend

A303691 a(n) is the number of 3-smooth numbers k such that prime(n)-k is also a prime number, where prime(n) stands for the n-th prime.

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

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

cp's OEIS Frontend

A303691 a(n) is the number of 3-smooth numbers k such that prime(n)-k is also a prime number, where prime(n) stands for the n-th prime.

Table of values

List of values

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

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

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