A322978 - cp's OEIS frontend

A322978 Number of even divisors d of 2n such that d-1 is prime.

n	a(n)
1	0
2	1
3	1
4	2
5	0
6	3
7	1
8	2
9	2
10	2
11	0
12	5
13	0
14	2
15	2
16	3
17	0
18	4
19	1
20	3
21	3
22	2
23	0
24	6
25	0
26	1
27	3
28	3
29	0
30	6
31	1
32	3
33	1
34	2
35	1
36	7
37	1
38	2
39	1
40	4
41	0
42	6
43	0
44	3
45	4
46	1
47	0
48	7
49	2
50	2
51	2
52	3
53	0
54	6
55	1
56	3
57	3
58	1
59	0
60	8
61	0
62	2
63	4
64	4
65	0
66	5
67	0
68	3
69	2
70	4
71	0
72	8
73	0
74	2
75	3
76	4
77	1
78	3
79	1
80	5
81	3
82	2
83	0
84	9
85	0
86	1
87	2
88	3
89	0
90	9
91	2
92	2
93	2
94	1
95	1
96	8
97	1
98	3
99	3
100	4
101	0
102	5
103	0
104	3
105	4

[0, 1, 1, 2, 0, 3, 1, 2, 2, 2, 0, 5, 0, 2, 2, 3, 0, 4, 1, 3, 3, 2, 0, 6, 0, 1, 3, 3, 0, 6, 1, 3, 1, 2, 1, 7, 1, 2, 1, 4, 0, 6, 0, 3, 4, 1, 0, 7, 2, 2, 2, 3, 0, 6, 1, 3, 3, 1, 0, 8, 0, 2, 4, 4, 0, 5, 0, 3, 2, 4, 0, 8, 0, 2, 3, 4, 1, 3, 1, 5, 3, 2, 0, 9, 0, 1, 2, 3, 0, 9, 2, 2, 2, 1, 1, 8, 1, 3, 3, 4, 0, 5, 0, 3, 4]

cp's OEIS Frontend

A322978 Number of even divisors d of 2n such that d-1 is prime.

Table of values

List of values

n	a(n)
1	0
2	1
3	1
4	2
5	0
6	3
7	1
8	2
9	2
10	2
11	0
12	5
13	0
14	2
15	2
16	3
17	0
18	4
19	1
20	3
21	3
22	2
23	0
24	6
25	0
26	1
27	3
28	3
29	0
30	6
31	1
32	3
33	1
34	2
35	1
36	7
37	1
38	2
39	1
40	4
41	0
42	6
43	0
44	3
45	4
46	1
47	0
48	7
49	2
50	2
51	2
52	3
53	0
54	6
55	1
56	3
57	3
58	1
59	0
60	8
61	0
62	2
63	4
64	4
65	0
66	5
67	0
68	3
69	2
70	4
71	0
72	8
73	0
74	2
75	3
76	4
77	1
78	3
79	1
80	5
81	3
82	2
83	0
84	9
85	0
86	1
87	2
88	3
89	0
90	9
91	2
92	2
93	2
94	1
95	1
96	8
97	1
98	3
99	3
100	4
101	0
102	5
103	0
104	3
105	4

n	a(n)
1	0
2	1
3	1
4	2
5	0
6	3
7	1
8	2
9	2
10	2
11	0
12	5
13	0
14	2
15	2
16	3
17	0
18	4
19	1
20	3
21	3
22	2
23	0
24	6
25	0
26	1
27	3
28	3
29	0
30	6
31	1
32	3
33	1
34	2
35	1
36	7
37	1
38	2
39	1
40	4
41	0
42	6
43	0
44	3
45	4
46	1
47	0
48	7
49	2
50	2
51	2
52	3
53	0
54	6
55	1
56	3
57	3
58	1
59	0
60	8
61	0
62	2
63	4
64	4
65	0
66	5
67	0
68	3
69	2
70	4
71	0
72	8
73	0
74	2
75	3
76	4
77	1
78	3
79	1
80	5
81	3
82	2
83	0
84	9
85	0
86	1
87	2
88	3
89	0
90	9
91	2
92	2
93	2
94	1
95	1
96	8
97	1
98	3
99	3
100	4
101	0
102	5
103	0
104	3
105	4

n	a(n)
1	0
2	1
3	1
4	2
5	0
6	3
7	1
8	2
9	2
10	2
11	0
12	5
13	0
14	2
15	2
16	3
17	0
18	4
19	1
20	3
21	3
22	2
23	0
24	6
25	0
26	1
27	3
28	3
29	0
30	6
31	1
32	3
33	1
34	2
35	1
36	7
37	1
38	2
39	1
40	4
41	0
42	6
43	0
44	3
45	4
46	1
47	0
48	7
49	2
50	2
51	2
52	3
53	0
54	6
55	1
56	3
57	3
58	1
59	0
60	8
61	0
62	2
63	4
64	4
65	0
66	5
67	0
68	3
69	2
70	4
71	0
72	8
73	0
74	2
75	3
76	4
77	1
78	3
79	1
80	5
81	3
82	2
83	0
84	9
85	0
86	1
87	2
88	3
89	0
90	9
91	2
92	2
93	2
94	1
95	1
96	8
97	1
98	3
99	3
100	4
101	0
102	5
103	0
104	3
105	4