A241539 - cp's OEIS frontend

A241539 Smallest k>=1 such that the n-th semiprime + or - k are both primes, or a(n)=0 if there is no such k.

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

[1, 1, 2, 3, 3, 2, 2, 9, 6, 3, 4, 3, 6, 9, 2, 15, 12, 8, 12, 4, 15, 9, 6, 2, 15, 6, 15, 12, 3, 14, 12, 4, 15, 6, 3, 2, 12, 9, 12, 18, 9, 14, 2, 6, 3, 10, 15, 6, 6, 33, 18, 9, 8, 12, 15, 12, 4, 15, 10, 6, 6, 3, 10, 9, 24, 6, 27, 18, 14, 15, 18, 6, 21, 8, 30, 3]

cp's OEIS Frontend

A241539 Smallest k>=1 such that the n-th semiprime + or - k are both primes, or a(n)=0 if there is no such k.

Table of values

List of values

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

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

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