A257459 - cp's OEIS frontend

A257459 Let b_k=1...1 consist of k>0 1'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	2
2	1
3	5
4	1
5	17
6	1
7	8
8	1
9	2
10	6
11	1
12	0
13	2
14	1
15	3
16	9
17	18
18	4
19	210
20	6
21	7
22	3
23	2
24	6
25	1
26	2
27	1
28	2
29	1
30	2
31	4
32	3
33	2
34	24
35	3
36	1
37	1
38	6
39	5
40	11
41	2
42	1
43	11
44	1
45	12
46	6
47	1
48	7
49	3
50	39
51	2
52	2
53	1
54	2
55	9
56	3
57	5
58	1
59	6
60	2
61	3
62	2
63	180
64	3
65	15
66	17
67	24
68	1
69	5
70	1
71	2
72	2
73	1
74	64
75	7
76	6
77	3
78	24
79	2
80	1
81	2
82	1
83	6
84	16
85	1
86	9
87	8
88	6
89	17
90	4
91	6
92	2
93	1
94	9
95	30
96	2
97	6
98	44
99	1
100	6

[2, 1, 5, 1, 17, 1, 8, 1, 2, 6, 1, 0, 2, 1, 3, 9, 18, 4, 210, 6, 7, 3, 2, 6, 1, 2, 1, 2, 1, 2, 4, 3, 2, 24, 3, 1, 1, 6, 5, 11, 2, 1, 11, 1, 12, 6, 1, 7, 3, 39, 2, 2, 1, 2, 9, 3, 5, 1, 6, 2, 3, 2, 180, 3, 15, 17, 24, 1, 5, 1, 2, 2, 1, 64, 7, 6, 3, 24, 2, 1, 2, 1, 6, 16, 1, 9, 8, 6, 17, 4, 6, 2, 1, 9, 30, 2, 6, 44, 1, 6]

cp's OEIS Frontend

A257459 Let b_k=1...1 consist of k>0 1'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	2
2	1
3	5
4	1
5	17
6	1
7	8
8	1
9	2
10	6
11	1
12	0
13	2
14	1
15	3
16	9
17	18
18	4
19	210
20	6
21	7
22	3
23	2
24	6
25	1
26	2
27	1
28	2
29	1
30	2
31	4
32	3
33	2
34	24
35	3
36	1
37	1
38	6
39	5
40	11
41	2
42	1
43	11
44	1
45	12
46	6
47	1
48	7
49	3
50	39
51	2
52	2
53	1
54	2
55	9
56	3
57	5
58	1
59	6
60	2
61	3
62	2
63	180
64	3
65	15
66	17
67	24
68	1
69	5
70	1
71	2
72	2
73	1
74	64
75	7
76	6
77	3
78	24
79	2
80	1
81	2
82	1
83	6
84	16
85	1
86	9
87	8
88	6
89	17
90	4
91	6
92	2
93	1
94	9
95	30
96	2
97	6
98	44
99	1
100	6

n	a(n)
1	2
2	1
3	5
4	1
5	17
6	1
7	8
8	1
9	2
10	6
11	1
12	0
13	2
14	1
15	3
16	9
17	18
18	4
19	210
20	6
21	7
22	3
23	2
24	6
25	1
26	2
27	1
28	2
29	1
30	2
31	4
32	3
33	2
34	24
35	3
36	1
37	1
38	6
39	5
40	11
41	2
42	1
43	11
44	1
45	12
46	6
47	1
48	7
49	3
50	39
51	2
52	2
53	1
54	2
55	9
56	3
57	5
58	1
59	6
60	2
61	3
62	2
63	180
64	3
65	15
66	17
67	24
68	1
69	5
70	1
71	2
72	2
73	1
74	64
75	7
76	6
77	3
78	24
79	2
80	1
81	2
82	1
83	6
84	16
85	1
86	9
87	8
88	6
89	17
90	4
91	6
92	2
93	1
94	9
95	30
96	2
97	6
98	44
99	1
100	6

n	a(n)
1	2
2	1
3	5
4	1
5	17
6	1
7	8
8	1
9	2
10	6
11	1
12	0
13	2
14	1
15	3
16	9
17	18
18	4
19	210
20	6
21	7
22	3
23	2
24	6
25	1
26	2
27	1
28	2
29	1
30	2
31	4
32	3
33	2
34	24
35	3
36	1
37	1
38	6
39	5
40	11
41	2
42	1
43	11
44	1
45	12
46	6
47	1
48	7
49	3
50	39
51	2
52	2
53	1
54	2
55	9
56	3
57	5
58	1
59	6
60	2
61	3
62	2
63	180
64	3
65	15
66	17
67	24
68	1
69	5
70	1
71	2
72	2
73	1
74	64
75	7
76	6
77	3
78	24
79	2
80	1
81	2
82	1
83	6
84	16
85	1
86	9
87	8
88	6
89	17
90	4
91	6
92	2
93	1
94	9
95	30
96	2
97	6
98	44
99	1
100	6