A085917 - cp's OEIS frontend

A085917 Least k such that k*2^n - 1 is a semiprime.

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

[5, 4, 2, 1, 3, 5, 4, 2, 1, 2, 1, 3, 6, 3, 3, 3, 3, 6, 3, 3, 3, 2, 1, 3, 6, 3, 6, 3, 6, 3, 3, 11, 16, 8, 4, 2, 1, 8, 4, 2, 1, 15, 13, 15, 16, 8, 4, 2, 1, 6, 3, 17, 15, 12, 6, 3, 4, 2, 1, 3, 6, 3, 3, 5, 3, 2, 1, 5, 6, 3, 48, 24, 12, 6, 3, 12, 6, 3, 10, 5, 4, 2, 1, 3, 3, 31, 21, 17, 15, 11, 13, 24, 12, 6, 3]

cp's OEIS Frontend

A085917 Least k such that k*2^n - 1 is a semiprime.

Table of values

List of values

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

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

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