A257461 - cp's OEIS frontend

A257461 Let b_k=9...9 consist of k>0 9's. Then a(n) is the smallest k such that the concatenation prime(n)b_k is prime, or a(n)=0 if there is no such prime.

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

[1, 0, 1, 1, 5, 1, 1, 1, 1, 2, 28, 1, 1, 1, 1, 2, 1, 1, 4, 1, 1, 3, 1, 2, 90, 1, 1, 2, 8, 2, 1, 1, 2, 1, 1, 2, 1, 4, 6, 8, 3, 2, 3, 4, 1, 1, 5, 1, 5, 60, 1, 1, 5, 6, 1, 2, 1, 1, 2, 1, 10, 1, 1, 1, 5, 2, 1, 3, 4, 1, 1, 2, 4, 1, 3, 4, 3, 2, 1, 1, 2, 1, 6, 1, 5, 3]

cp's OEIS Frontend

A257461 Let b_k=9...9 consist of k>0 9's. Then a(n) is the smallest k such that the concatenation prime(n)b_k is prime, or a(n)=0 if there is no such prime.

Table of values

List of values

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

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

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