A306259 - cp's OEIS frontend

A306259 Composite numbers k such that 2^(k(k-1)) == 1 (mod k^2).

n	a(n)
1	21
2	105
3	165
4	205
5	231
6	273
7	301
8	341
9	385
10	465
11	561
12	609
13	645
14	651
15	861
16	889
17	903
18	1045
19	1065
20	1105
21	1265
22	1281
23	1365
24	1387
25	1491
26	1705
27	1729
28	1771
29	1785
30	1905
31	2041
32	2047
33	2145
34	2211
35	2265
36	2329
37	2359
38	2373
39	2465
40	2485
41	2665
42	2667
43	2701
44	2821
45	3045
46	3081
47	3165
48	3171
49	3201
50	3277

[21, 105, 165, 205, 231, 273, 301, 341, 385, 465, 561, 609, 645, 651, 861, 889, 903, 1045, 1065, 1105, 1265, 1281, 1365, 1387, 1491, 1705, 1729, 1771, 1785, 1905, 2041, 2047, 2145, 2211, 2265, 2329, 2359, 2373, 2465, 2485, 2665, 2667, 2701, 2821, 3045, 3081, 3165, 3171, 3201, 3277]

cp's OEIS Frontend

A306259 Composite numbers k such that 2^(k(k-1)) == 1 (mod k^2).

Table of values

List of values