A194606 - cp's OEIS frontend

A194606 Least k >= 0 such that prime(n)2^k - 1 or prime(n)2^k + 1 is prime, or -1 if no such value exists, where prime(n) denotes the n-th prime number.

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

[0, 0, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 2, 4, 1, 5, 3, 2, 2, 2, 1, 1, 1, 1, 3, 3, 3, 6, 1, 2, 1, 2, 1, 3, 4, 1, 2, 4, 1, 1, 3, 1, 2, 2, 1, 1, 3, 2, 1, 1, 1, 11, 1, 4, 2, 3, 1, 2, 1, 11, 1, 1, 9, 3, 6, 1, 1, 3, 3, 4, 1, 1, 2, 1, 2, 11, 4, 3, 2, 1, 4, 1, 2, 1, 1]

cp's OEIS Frontend

A194606 Least k >= 0 such that prime(n)2^k - 1 or prime(n)2^k + 1 is prime, or -1 if no such value exists, where prime(n) denotes the n-th prime number.

Table of values

List of values

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

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

cp's OEIS Frontend

A194606 Least k >= 0 such that prime(n)*2^k - 1 or prime(n)*2^k + 1 is prime, or -1 if no such value exists, where prime(n) denotes the n-th prime number.

Table of values

List of values

A194606 Least k >= 0 such that prime(n)2^k - 1 or prime(n)2^k + 1 is prime, or -1 if no such value exists, where prime(n) denotes the n-th prime number.

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