A055557 - cp's OEIS frontend

A055557 Numbers k such that 3*R_k - 2 is prime, where R_k = 11...1 is the repunit (A002275) of length k.

n	a(n)
1	2
2	3
3	4
4	5
5	6
6	7
7	8
8	18
9	40
10	50
11	60
12	78
13	101
14	151
15	319
16	382
17	784
18	1732
19	1918
20	8855
21	11245
22	11960
23	12130
24	18533
25	22718
26	23365
27	24253
28	24549
29	25324
30	30178
31	53718
32	380976
33	424861
34	563535
35	666903

[2, 3, 4, 5, 6, 7, 8, 18, 40, 50, 60, 78, 101, 151, 319, 382, 784, 1732, 1918, 8855, 11245, 11960, 12130, 18533, 22718, 23365, 24253, 24549, 25324, 30178, 53718, 380976, 424861, 563535, 666903]

cp's OEIS Frontend

A055557 Numbers k such that 3*R_k - 2 is prime, where R_k = 11...1 is the repunit (A002275) of length k.

Table of values

List of values