A101050 - cp's OEIS frontend

A101050 Least k such that prime(n)*2^k-1 is prime, or -1 if no such k exists.

n	a(n)
1	1
2	0
3	2
4	1
5	2
6	3
7	2
8	1
9	4
10	4
11	1
12	1
13	2
14	7
15	4
16	2
17	12
18	3
19	5
20	2
21	7
22	1
23	2
24	4
25	1
26	10
27	3
28	10
29	9
30	8
31	25
32	2
33	2
34	1
35	4
36	5
37	1
38	3
39	4
40	2
41	8
42	3
43	226
44	3
45	2
46	1
47	1
48	3
49	2
50	1
51	4
52	4
53	11
54	6
55	4
56	2
57	8
58	1
59	5
60	2
61	11
62	2
63	1
64	26
65	3
66	6
67	1
68	1
69	18
70	3
71	4
72	4
73	1
74	7
75	1
76	2
77	20
78	5
79	10
80	3
81	4
82	7
83	2
84	3
85	1
86	6
87	112
88	9
89	10
90	7
91	2
92	12
93	5
94	46
95	1
96	2
97	8

[1, 0, 2, 1, 2, 3, 2, 1, 4, 4, 1, 1, 2, 7, 4, 2, 12, 3, 5, 2, 7, 1, 2, 4, 1, 10, 3, 10, 9, 8, 25, 2, 2, 1, 4, 5, 1, 3, 4, 2, 8, 3, 226, 3, 2, 1, 1, 3, 2, 1, 4, 4, 11, 6, 4, 2, 8, 1, 5, 2, 11, 2, 1, 26, 3, 6, 1, 1, 18, 3, 4, 4, 1, 7, 1, 2, 20, 5, 10, 3, 4, 7, 2, 3, 1, 6, 112, 9, 10, 7, 2, 12, 5, 46, 1, 2, 8]

cp's OEIS Frontend

A101050 Least k such that prime(n)*2^k-1 is prime, or -1 if no such k exists.

Table of values

List of values

n	a(n)
1	1
2	0
3	2
4	1
5	2
6	3
7	2
8	1
9	4
10	4
11	1
12	1
13	2
14	7
15	4
16	2
17	12
18	3
19	5
20	2
21	7
22	1
23	2
24	4
25	1
26	10
27	3
28	10
29	9
30	8
31	25
32	2
33	2
34	1
35	4
36	5
37	1
38	3
39	4
40	2
41	8
42	3
43	226
44	3
45	2
46	1
47	1
48	3
49	2
50	1
51	4
52	4
53	11
54	6
55	4
56	2
57	8
58	1
59	5
60	2
61	11
62	2
63	1
64	26
65	3
66	6
67	1
68	1
69	18
70	3
71	4
72	4
73	1
74	7
75	1
76	2
77	20
78	5
79	10
80	3
81	4
82	7
83	2
84	3
85	1
86	6
87	112
88	9
89	10
90	7
91	2
92	12
93	5
94	46
95	1
96	2
97	8

n	a(n)
1	1
2	0
3	2
4	1
5	2
6	3
7	2
8	1
9	4
10	4
11	1
12	1
13	2
14	7
15	4
16	2
17	12
18	3
19	5
20	2
21	7
22	1
23	2
24	4
25	1
26	10
27	3
28	10
29	9
30	8
31	25
32	2
33	2
34	1
35	4
36	5
37	1
38	3
39	4
40	2
41	8
42	3
43	226
44	3
45	2
46	1
47	1
48	3
49	2
50	1
51	4
52	4
53	11
54	6
55	4
56	2
57	8
58	1
59	5
60	2
61	11
62	2
63	1
64	26
65	3
66	6
67	1
68	1
69	18
70	3
71	4
72	4
73	1
74	7
75	1
76	2
77	20
78	5
79	10
80	3
81	4
82	7
83	2
84	3
85	1
86	6
87	112
88	9
89	10
90	7
91	2
92	12
93	5
94	46
95	1
96	2
97	8

n	a(n)
1	1
2	0
3	2
4	1
5	2
6	3
7	2
8	1
9	4
10	4
11	1
12	1
13	2
14	7
15	4
16	2
17	12
18	3
19	5
20	2
21	7
22	1
23	2
24	4
25	1
26	10
27	3
28	10
29	9
30	8
31	25
32	2
33	2
34	1
35	4
36	5
37	1
38	3
39	4
40	2
41	8
42	3
43	226
44	3
45	2
46	1
47	1
48	3
49	2
50	1
51	4
52	4
53	11
54	6
55	4
56	2
57	8
58	1
59	5
60	2
61	11
62	2
63	1
64	26
65	3
66	6
67	1
68	1
69	18
70	3
71	4
72	4
73	1
74	7
75	1
76	2
77	20
78	5
79	10
80	3
81	4
82	7
83	2
84	3
85	1
86	6
87	112
88	9
89	10
90	7
91	2
92	12
93	5
94	46
95	1
96	2
97	8