A232084 - cp's OEIS frontend

A232084 Least k such that prime(n) + 2^(k+L) - 2^L is a prime, where L is the length of binary representation of prime(n): L = A070939(A000040(n)). a(n) = -1 if no such k exists.

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

[1, 1, 2, 2, 1, 2, 4, 4, 1, 2, 1, 2, 1, 2, 4, 2, 3, 4, 1, 2, 2, 1, 5, 4, 1, 2, 2, 4, 1, 6, 18, 20, 2, 4, 2, 3, 1, 4, 2, 2, 3, 6, 1, 12, 2, 1, 1, 96, 2, 4, 4, 2, 2, 1, 3, 3, 4, 6, 6, 4, 3, 6, 1, 4, 1, 2, 2, 1, 56, 2, 3, 8, 4, 4, 3, 4, 2, 4, 4, 3, 4, 4, 18, 20, 2, 8, 2, 2]

cp's OEIS Frontend

A232084 Least k such that prime(n) + 2^(k+L) - 2^L is a prime, where L is the length of binary representation of prime(n): L = A070939(A000040(n)). a(n) = -1 if no such k exists.

Table of values

List of values

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

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

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