A241656 - cp's OEIS frontend

A241656 Smallest semiprime, sp, such that 2n - sp is a semiprime, or a(n)=0 if there is no such sp.

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

[0, 0, 0, 4, 4, 6, 4, 6, 4, 6, 0, 9, 4, 6, 4, 6, 9, 10, 4, 6, 4, 6, 21, 9, 4, 6, 15, 10, 9, 9, 4, 6, 4, 6, 15, 10, 9, 14, 4, 6, 25, 10, 4, 6, 4, 6, 9, 9, 4, 6, 9, 9, 15, 14, 4, 6, 21, 10, 25, 9, 4, 6, 4, 6, 9, 9, 15, 14, 4, 6, 9, 10, 4, 6, 4, 6, 9, 10, 15, 14, 4, 6, 21, 9, 4, 6, 15, 10, 9, 14]

cp's OEIS Frontend

A241656 Smallest semiprime, sp, such that 2n - sp is a semiprime, or a(n)=0 if there is no such sp.

Table of values

List of values

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

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

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