A194591 - cp's OEIS frontend

A194591 Least k >= 0 such that n2^k - 1 or n2^k + 1 is prime, or -1 if no such value exists.

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

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

cp's OEIS Frontend

A194591 Least k >= 0 such that n2^k - 1 or n2^k + 1 is prime, or -1 if no such value exists.

Table of values

List of values

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

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

cp's OEIS Frontend

A194591 Least k >= 0 such that n*2^k - 1 or n*2^k + 1 is prime, or -1 if no such value exists.

Table of values

List of values

A194591 Least k >= 0 such that n2^k - 1 or n2^k + 1 is prime, or -1 if no such value exists.

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