A187467 - cp's OEIS frontend

A187467 Least k > 1 such that prime(k)*2^n - 1 is prime, or zero if never prime.

n	a(n)
1	2
2	2
3	2
4	2
5	4
6	2
7	2
8	3
9	4
10	3
11	2
12	3
13	11
14	3
15	22
16	7
17	4
18	2
19	18
20	7
21	4
22	23
23	6
24	23
25	18
26	5
27	44
28	23
29	4
30	98
31	14
32	3
33	11
34	2
35	11
36	7
37	11
38	2
39	18
40	28
41	8
42	16
43	2
44	102
45	4
46	9
47	11
48	3
49	8
50	5
51	174
52	24
53	63
54	3
55	2
56	103
57	22
58	23
59	130
60	7
61	22
62	16
63	18
64	2

[2, 2, 2, 2, 4, 2, 2, 3, 4, 3, 2, 3, 11, 3, 22, 7, 4, 2, 18, 7, 4, 23, 6, 23, 18, 5, 44, 23, 4, 98, 14, 3, 11, 2, 11, 7, 11, 2, 18, 28, 8, 16, 2, 102, 4, 9, 11, 3, 8, 5, 174, 24, 63, 3, 2, 103, 22, 23, 130, 7, 22, 16, 18, 2]

cp's OEIS Frontend

A187467 Least k > 1 such that prime(k)*2^n - 1 is prime, or zero if never prime.

Table of values

List of values

n	a(n)
1	2
2	2
3	2
4	2
5	4
6	2
7	2
8	3
9	4
10	3
11	2
12	3
13	11
14	3
15	22
16	7
17	4
18	2
19	18
20	7
21	4
22	23
23	6
24	23
25	18
26	5
27	44
28	23
29	4
30	98
31	14
32	3
33	11
34	2
35	11
36	7
37	11
38	2
39	18
40	28
41	8
42	16
43	2
44	102
45	4
46	9
47	11
48	3
49	8
50	5
51	174
52	24
53	63
54	3
55	2
56	103
57	22
58	23
59	130
60	7
61	22
62	16
63	18
64	2

n	a(n)
1	2
2	2
3	2
4	2
5	4
6	2
7	2
8	3
9	4
10	3
11	2
12	3
13	11
14	3
15	22
16	7
17	4
18	2
19	18
20	7
21	4
22	23
23	6
24	23
25	18
26	5
27	44
28	23
29	4
30	98
31	14
32	3
33	11
34	2
35	11
36	7
37	11
38	2
39	18
40	28
41	8
42	16
43	2
44	102
45	4
46	9
47	11
48	3
49	8
50	5
51	174
52	24
53	63
54	3
55	2
56	103
57	22
58	23
59	130
60	7
61	22
62	16
63	18
64	2

n	a(n)
1	2
2	2
3	2
4	2
5	4
6	2
7	2
8	3
9	4
10	3
11	2
12	3
13	11
14	3
15	22
16	7
17	4
18	2
19	18
20	7
21	4
22	23
23	6
24	23
25	18
26	5
27	44
28	23
29	4
30	98
31	14
32	3
33	11
34	2
35	11
36	7
37	11
38	2
39	18
40	28
41	8
42	16
43	2
44	102
45	4
46	9
47	11
48	3
49	8
50	5
51	174
52	24
53	63
54	3
55	2
56	103
57	22
58	23
59	130
60	7
61	22
62	16
63	18
64	2