A238797 - cp's OEIS frontend

A238797 Smallest k such that 2^k - (2n+1) and (2n+1)2^k - 1 are both prime, k <= 2n+1, or 0 if no such k exists.

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

[0, 3, 4, 0, 0, 0, 0, 5, 6, 5, 7, 6, 9, 5, 0, 7, 6, 6, 0, 0, 10, 0, 6, 0, 7, 9, 6, 7, 8, 0, 17, 8, 0, 0, 7, 0, 0, 18, 0, 0, 0, 8, 0, 10, 8, 9, 18, 0, 0, 7, 0, 0, 8, 12, 0, 7, 0, 11, 16, 0, 21, 0, 0, 0, 8, 14, 0, 0, 18, 9, 10, 8, 77, 0, 0, 0, 12, 8, 0, 11, 18, 0]

cp's OEIS Frontend

A238797 Smallest k such that 2^k - (2n+1) and (2n+1)2^k - 1 are both prime, k <= 2n+1, or 0 if no such k exists.

Table of values

List of values

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

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

cp's OEIS Frontend

A238797 Smallest k such that 2^k - (2*n+1) and (2*n+1)*2^k - 1 are both prime, k <= 2*n+1, or 0 if no such k exists.

Table of values

List of values

A238797 Smallest k such that 2^k - (2n+1) and (2n+1)2^k - 1 are both prime, k <= 2n+1, or 0 if no such k exists.

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