A098088 - cp's OEIS frontend

A098088 Numbers k such that 6*R_k - 5 is prime, where R_k = 11...1 is the repunit (A002275) of length k.

n	a(n)
1	2
2	3
3	4
4	10
5	18
6	21
7	22
8	28
9	43
10	66
11	121
12	133
13	178
14	241
15	454
16	553
17	1600
18	2175
19	2978
20	3649
21	7708
22	8316
23	10392
24	12458
25	21057
26	26223
27	48297
28	64041
29	84904
30	92976
31	95072
32	103161
33	140461
34	141751
35	150612
36	265321
37	672745

[2, 3, 4, 10, 18, 21, 22, 28, 43, 66, 121, 133, 178, 241, 454, 553, 1600, 2175, 2978, 3649, 7708, 8316, 10392, 12458, 21057, 26223, 48297, 64041, 84904, 92976, 95072, 103161, 140461, 141751, 150612, 265321, 672745]

cp's OEIS Frontend

A098088 Numbers k such that 6*R_k - 5 is prime, where R_k = 11...1 is the repunit (A002275) of length k.

Table of values

List of values