A124522 - cp's OEIS frontend

A124522 a(n) = smallest k such that 2nk-1 and 2nk+1 are primes.

n	a(n)
1	2
2	1
3	1
4	9
5	3
6	1
7	3
8	12
9	1
10	3
11	9
12	3
13	12
14	15
15	1
16	6
17	3
18	2
19	6
20	6
21	1
22	15
23	3
24	4
25	3
26	6
27	2
28	48
29	6
30	1
31	21
32	3
33	3
34	15
35	6
36	1
37	27
38	3
39	4
40	3
41	15
42	5
43	12
44	15
45	2
46	9
47	3
48	2
49	9
50	6
51	1
52	3
53	60
54	1
55	6
56	24
57	2
58	3
59	9
60	2
61	129
62	12
63	7
64	9
65	15
66	5
67	12
68	27
69	1
70	3
71	9
72	3
73	42
74	45
75	1
76	90
77	3
78	2
79	66
80	21
81	5
82	63
83	27
84	16
85	6
86	6
87	2
88	12
89	24
90	1
91	6

[2, 1, 1, 9, 3, 1, 3, 12, 1, 3, 9, 3, 12, 15, 1, 6, 3, 2, 6, 6, 1, 15, 3, 4, 3, 6, 2, 48, 6, 1, 21, 3, 3, 15, 6, 1, 27, 3, 4, 3, 15, 5, 12, 15, 2, 9, 3, 2, 9, 6, 1, 3, 60, 1, 6, 24, 2, 3, 9, 2, 129, 12, 7, 9, 15, 5, 12, 27, 1, 3, 9, 3, 42, 45, 1, 90, 3, 2, 66, 21, 5, 63, 27, 16, 6, 6, 2, 12, 24, 1, 6]

cp's OEIS Frontend

A124522 a(n) = smallest k such that 2nk-1 and 2nk+1 are primes.

Table of values

List of values

n	a(n)
1	2
2	1
3	1
4	9
5	3
6	1
7	3
8	12
9	1
10	3
11	9
12	3
13	12
14	15
15	1
16	6
17	3
18	2
19	6
20	6
21	1
22	15
23	3
24	4
25	3
26	6
27	2
28	48
29	6
30	1
31	21
32	3
33	3
34	15
35	6
36	1
37	27
38	3
39	4
40	3
41	15
42	5
43	12
44	15
45	2
46	9
47	3
48	2
49	9
50	6
51	1
52	3
53	60
54	1
55	6
56	24
57	2
58	3
59	9
60	2
61	129
62	12
63	7
64	9
65	15
66	5
67	12
68	27
69	1
70	3
71	9
72	3
73	42
74	45
75	1
76	90
77	3
78	2
79	66
80	21
81	5
82	63
83	27
84	16
85	6
86	6
87	2
88	12
89	24
90	1
91	6

n	a(n)
1	2
2	1
3	1
4	9
5	3
6	1
7	3
8	12
9	1
10	3
11	9
12	3
13	12
14	15
15	1
16	6
17	3
18	2
19	6
20	6
21	1
22	15
23	3
24	4
25	3
26	6
27	2
28	48
29	6
30	1
31	21
32	3
33	3
34	15
35	6
36	1
37	27
38	3
39	4
40	3
41	15
42	5
43	12
44	15
45	2
46	9
47	3
48	2
49	9
50	6
51	1
52	3
53	60
54	1
55	6
56	24
57	2
58	3
59	9
60	2
61	129
62	12
63	7
64	9
65	15
66	5
67	12
68	27
69	1
70	3
71	9
72	3
73	42
74	45
75	1
76	90
77	3
78	2
79	66
80	21
81	5
82	63
83	27
84	16
85	6
86	6
87	2
88	12
89	24
90	1
91	6

n	a(n)
1	2
2	1
3	1
4	9
5	3
6	1
7	3
8	12
9	1
10	3
11	9
12	3
13	12
14	15
15	1
16	6
17	3
18	2
19	6
20	6
21	1
22	15
23	3
24	4
25	3
26	6
27	2
28	48
29	6
30	1
31	21
32	3
33	3
34	15
35	6
36	1
37	27
38	3
39	4
40	3
41	15
42	5
43	12
44	15
45	2
46	9
47	3
48	2
49	9
50	6
51	1
52	3
53	60
54	1
55	6
56	24
57	2
58	3
59	9
60	2
61	129
62	12
63	7
64	9
65	15
66	5
67	12
68	27
69	1
70	3
71	9
72	3
73	42
74	45
75	1
76	90
77	3
78	2
79	66
80	21
81	5
82	63
83	27
84	16
85	6
86	6
87	2
88	12
89	24
90	1
91	6