A242775 - cp's OEIS frontend

A242775 Let b_k=3...3 consist of k>=1 3's. Then a(n) is the smallest k such that the concatenation b_k and prime(n) is prime, or a(n)=0 if there is no such prime.

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

[0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 1, 1, 4, 2, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 3, 3, 2, 1, 2, 7, 3, 1, 3, 2, 2, 8, 1, 1, 7, 2, 1, 1, 5, 3, 2, 2, 2, 3, 1, 3, 8, 5, 1, 1, 4, 3, 1, 4, 5, 3, 6, 1, 2, 1, 2, 1, 3, 1, 2, 2, 1, 3, 1, 6, 3, 1, 3, 4, 2, 3, 8, 4, 1, 3, 34, 1]

cp's OEIS Frontend

A242775 Let b_k=3...3 consist of k>=1 3's. Then a(n) is the smallest k such that the concatenation b_k and prime(n) is prime, or a(n)=0 if there is no such prime.

Table of values

List of values

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

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

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