A301806 - cp's OEIS frontend

A301806 Numbers k such that the concatenation of 2^k - 1 and 2^(k - 1) - 1 is prime.

n	a(n)
1	2
2	3
3	4
4	7
5	8
6	12
7	19
8	22
9	36
10	46
11	51
12	67
13	79
14	215
15	359
16	394
17	451
18	1323
19	2131
20	3336
21	3371
22	6231
23	19179
24	39699
25	51456
26	56238
27	69660
28	75894
29	79798
30	92020
31	174968
32	176006
33	181015
34	285019
35	331259
36	360787
37	366770

[2, 3, 4, 7, 8, 12, 19, 22, 36, 46, 51, 67, 79, 215, 359, 394, 451, 1323, 2131, 3336, 3371, 6231, 19179, 39699, 51456, 56238, 69660, 75894, 79798, 92020, 174968, 176006, 181015, 285019, 331259, 360787, 366770]

cp's OEIS Frontend

A301806 Numbers k such that the concatenation of 2^k - 1 and 2^(k - 1) - 1 is prime.

Table of values

List of values