A067760 - cp's OEIS frontend

A067760 a(n) is the least positive k such that (2n+1) + 2^k is prime, or 0 if no such k exists.

n	a(n)
0	1
1	1
2	1
3	2
4	1
5	1
6	2
7	1
8	1
9	2
10	1
11	3
12	2
13	1
14	1
15	4
16	2
17	1
18	2
19	1
20	1
21	2
22	1
23	5
24	2
25	1
26	3
27	2
28	1
29	1
30	8
31	2
32	1
33	2
34	1
35	1
36	4
37	2
38	1
39	2
40	1
41	7
42	2
43	1
44	3
45	4
46	2
47	1
48	2
49	1
50	1
51	2
52	1
53	1
54	2
55	1
56	7
57	4
58	5
59	3
60	4
61	2
62	1
63	2
64	1
65	3
66	2
67	1
68	1
69	10
70	3
71	3
72	2
73	1
74	1
75	4
76	2
77	1
78	4
79	2
80	1
81	2
82	1
83	5
84	2
85	1
86	3
87	2
88	1
89	1
90	4
91	3
92	3
93	2
94	1
95	1
96	2
97	1
98	1
99	6
100	5
101	3
102	6

[1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 3, 2, 1, 1, 4, 2, 1, 2, 1, 1, 2, 1, 5, 2, 1, 3, 2, 1, 1, 8, 2, 1, 2, 1, 1, 4, 2, 1, 2, 1, 7, 2, 1, 3, 4, 2, 1, 2, 1, 1, 2, 1, 1, 2, 1, 7, 4, 5, 3, 4, 2, 1, 2, 1, 3, 2, 1, 1, 10, 3, 3, 2, 1, 1, 4, 2, 1, 4, 2, 1, 2, 1, 5, 2, 1, 3, 2, 1, 1, 4, 3, 3, 2, 1, 1, 2, 1, 1, 6, 5, 3, 6]

cp's OEIS Frontend

A067760 a(n) is the least positive k such that (2n+1) + 2^k is prime, or 0 if no such k exists.

Table of values

List of values

n	a(n)
0	1
1	1
2	1
3	2
4	1
5	1
6	2
7	1
8	1
9	2
10	1
11	3
12	2
13	1
14	1
15	4
16	2
17	1
18	2
19	1
20	1
21	2
22	1
23	5
24	2
25	1
26	3
27	2
28	1
29	1
30	8
31	2
32	1
33	2
34	1
35	1
36	4
37	2
38	1
39	2
40	1
41	7
42	2
43	1
44	3
45	4
46	2
47	1
48	2
49	1
50	1
51	2
52	1
53	1
54	2
55	1
56	7
57	4
58	5
59	3
60	4
61	2
62	1
63	2
64	1
65	3
66	2
67	1
68	1
69	10
70	3
71	3
72	2
73	1
74	1
75	4
76	2
77	1
78	4
79	2
80	1
81	2
82	1
83	5
84	2
85	1
86	3
87	2
88	1
89	1
90	4
91	3
92	3
93	2
94	1
95	1
96	2
97	1
98	1
99	6
100	5
101	3
102	6

n	a(n)
0	1
1	1
2	1
3	2
4	1
5	1
6	2
7	1
8	1
9	2
10	1
11	3
12	2
13	1
14	1
15	4
16	2
17	1
18	2
19	1
20	1
21	2
22	1
23	5
24	2
25	1
26	3
27	2
28	1
29	1
30	8
31	2
32	1
33	2
34	1
35	1
36	4
37	2
38	1
39	2
40	1
41	7
42	2
43	1
44	3
45	4
46	2
47	1
48	2
49	1
50	1
51	2
52	1
53	1
54	2
55	1
56	7
57	4
58	5
59	3
60	4
61	2
62	1
63	2
64	1
65	3
66	2
67	1
68	1
69	10
70	3
71	3
72	2
73	1
74	1
75	4
76	2
77	1
78	4
79	2
80	1
81	2
82	1
83	5
84	2
85	1
86	3
87	2
88	1
89	1
90	4
91	3
92	3
93	2
94	1
95	1
96	2
97	1
98	1
99	6
100	5
101	3
102	6

n	a(n)
0	1
1	1
2	1
3	2
4	1
5	1
6	2
7	1
8	1
9	2
10	1
11	3
12	2
13	1
14	1
15	4
16	2
17	1
18	2
19	1
20	1
21	2
22	1
23	5
24	2
25	1
26	3
27	2
28	1
29	1
30	8
31	2
32	1
33	2
34	1
35	1
36	4
37	2
38	1
39	2
40	1
41	7
42	2
43	1
44	3
45	4
46	2
47	1
48	2
49	1
50	1
51	2
52	1
53	1
54	2
55	1
56	7
57	4
58	5
59	3
60	4
61	2
62	1
63	2
64	1
65	3
66	2
67	1
68	1
69	10
70	3
71	3
72	2
73	1
74	1
75	4
76	2
77	1
78	4
79	2
80	1
81	2
82	1
83	5
84	2
85	1
86	3
87	2
88	1
89	1
90	4
91	3
92	3
93	2
94	1
95	1
96	2
97	1
98	1
99	6
100	5
101	3
102	6