A285770 - cp's OEIS frontend

A285770 Let q_1 be primes not dividing 2n+1 such that 2n-q_i + 1 is twice a prime. a(n) is smallest i such that 2n+2q_i+1 is prime or a(n)=0 if there is no such i.

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

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

cp's OEIS Frontend

A285770 Let q_1 be primes not dividing 2n+1 such that 2n-q_i + 1 is twice a prime. a(n) is smallest i such that 2n+2q_i+1 is prime or a(n)=0 if there is no such i.

Table of values

List of values

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

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

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