A280667 - cp's OEIS frontend

A280667 a(n) = number of primes of the form 4k + 1 such that 2n - 4k - 1 is prime.

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

[0, 0, 0, 1, 1, 1, 0, 2, 2, 2, 2, 3, 1, 2, 2, 2, 3, 4, 0, 3, 4, 3, 4, 5, 2, 3, 4, 3, 5, 6, 0, 5, 6, 2, 4, 6, 3, 5, 6, 4, 3, 8, 2, 4, 6, 4, 4, 7, 2, 6, 8, 5, 5, 8, 4, 7, 10, 6, 6, 12, 3, 5, 10, 3, 6, 9, 4, 5, 6, 7, 8, 11, 3, 5, 10, 4, 8, 11, 2, 8, 10, 5, 6, 13, 6, 6, 8, 7, 7, 14, 2, 8, 12, 5]

cp's OEIS Frontend

A280667 a(n) = number of primes of the form 4k + 1 such that 2n - 4k - 1 is prime.

Table of values

List of values

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

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

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