A276417 - cp's OEIS frontend

A276417 a(n) = least positive k such that (2*n + 1) - 2^k is prime, or 0 if no such k exists.

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

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

cp's OEIS Frontend

A276417 a(n) = least positive k such that (2*n + 1) - 2^k is prime, or 0 if no such k exists.

Table of values

List of values

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

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

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