A231561 - cp's OEIS frontend

A231561 Number of ways to write n = x + y with 0 < x <= y such that 2^x * y + 1 is prime.

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

[0, 1, 1, 1, 1, 2, 1, 1, 2, 2, 3, 3, 2, 1, 4, 5, 2, 2, 3, 3, 2, 2, 2, 4, 4, 3, 5, 4, 4, 3, 5, 4, 5, 4, 3, 3, 2, 3, 5, 5, 4, 4, 3, 3, 7, 5, 6, 4, 6, 5, 4, 6, 5, 5, 5, 3, 5, 6, 7, 8, 4, 4, 3, 4, 2, 3, 5, 6, 7, 7, 4, 3, 6, 6, 6, 8, 3, 4, 7, 7, 6, 6, 5, 7, 6, 7, 8, 5, 6, 5, 7, 2, 5, 5, 7, 5, 7, 6, 10, 8]

cp's OEIS Frontend

A231561 Number of ways to write n = x + y with 0 < x <= y such that 2^x * y + 1 is prime.

Table of values

List of values

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

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

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