A085427 - cp's OEIS frontend

A085427 Least k such that k*2^n - 1 is prime.

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

[3, 2, 1, 1, 2, 1, 2, 1, 5, 7, 5, 3, 2, 1, 5, 4, 2, 1, 2, 1, 14, 7, 26, 13, 39, 22, 11, 16, 8, 4, 2, 1, 5, 6, 3, 24, 12, 6, 3, 25, 24, 12, 6, 3, 14, 7, 20, 10, 5, 19, 11, 21, 20, 10, 5, 3, 32, 16, 8, 4, 2, 1, 12, 6, 3, 67, 63, 43, 63, 40, 20, 10, 5, 15, 12, 6, 3, 55, 47, 30, 15, 30, 15, 64, 32, 16, 8]

cp's OEIS Frontend

A085427 Least k such that k*2^n - 1 is prime.

Table of values

List of values

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

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

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