A111471 - cp's OEIS frontend

A111471 a(1) = 1; for n>1, a(n) = least k such that concatenation of n copies of k with all previous concatenations gives a prime.

n	a(n)
1	1
2	9
3	7
4	3
5	29
6	19
7	21
8	121
9	7
10	211
11	207
12	11
13	221
14	347
15	99
16	123
17	303
18	189
19	1131
20	1179
21	2069
22	3437
23	2211
24	211
25	3169
26	1551
27	3493
28	7433
29	6939
30	1053
31	1537
32	9417
33	4491
34	1257
35	19693
36	9
37	1653
38	3329
39	317
40	8667
41	799
42	1053
43	5617
44	6049
45	1721
46	24871
47	2751
48	737
49	3303
50	29079

[1, 9, 7, 3, 29, 19, 21, 121, 7, 211, 207, 11, 221, 347, 99, 123, 303, 189, 1131, 1179, 2069, 3437, 2211, 211, 3169, 1551, 3493, 7433, 6939, 1053, 1537, 9417, 4491, 1257, 19693, 9, 1653, 3329, 317, 8667, 799, 1053, 5617, 6049, 1721, 24871, 2751, 737, 3303, 29079]

cp's OEIS Frontend

A111471 a(1) = 1; for n>1, a(n) = least k such that concatenation of n copies of k with all previous concatenations gives a prime.

Table of values

List of values