A384958 - cp's OEIS frontend

A384958 a(n) is the first prime p such that the concatenations of n consecutive primes, starting with p, in both forward and backward directions, are prime.

n	a(n)
1	2
2	199
3	313
4	139
5	67
6	113
7	163
8	1583
9	23789
10	941
11	131
12	5351
13	26801
14	2693
15	4073
16	15859
17	4919
18	23209
19	176053
20	86783
21	29717
22	20849
23	151289
24	50111
25	51971
26	23689
27	11807
28	180337
29	563
30	25153
31	517381
32	36313
33	256121
34	753091
35	208441
36	28573
37	4049
38	108943
39	451361
40	114343
41	28447
42	21001
43	4001
44	3137
45	6833
46	885919

[2, 199, 313, 139, 67, 113, 163, 1583, 23789, 941, 131, 5351, 26801, 2693, 4073, 15859, 4919, 23209, 176053, 86783, 29717, 20849, 151289, 50111, 51971, 23689, 11807, 180337, 563, 25153, 517381, 36313, 256121, 753091, 208441, 28573, 4049, 108943, 451361, 114343, 28447, 21001, 4001, 3137, 6833, 885919]

cp's OEIS Frontend

A384958 a(n) is the first prime p such that the concatenations of n consecutive primes, starting with p, in both forward and backward directions, are prime.

Table of values

List of values