A382447 - cp's OEIS frontend

A382447 Number of positive k <= n such that k*2^n - 1 is prime.

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

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

cp's OEIS Frontend

A382447 Number of positive k <= n such that k*2^n - 1 is prime.

Table of values

List of values

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

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

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