A256517 - cp's OEIS frontend

A256517 Let c be the n-th composite number. Then a(n) is the smallest base b > 1 such that b^(c-1) == 1 (mod c^2), i.e., such that c is a 'Wieferich pseudoprime'.

n	a(n)
1	17
2	37
3	65
4	80
5	101
6	145
7	197
8	26
9	257
10	325
11	401
12	197
13	485
14	577
15	182
16	677
17	728
18	177
19	901
20	1025
21	485
22	1157
23	99
24	1297
25	1445
26	170
27	1601
28	1765
29	1937
30	82
31	2117
32	2305
33	1047
34	2501
35	577
36	529
37	2917
38	1451
39	3137
40	721
41	3365
42	3601
43	3845
44	244
45	4097
46	99
47	1945
48	4625
49	530

[17, 37, 65, 80, 101, 145, 197, 26, 257, 325, 401, 197, 485, 577, 182, 677, 728, 177, 901, 1025, 485, 1157, 99, 1297, 1445, 170, 1601, 1765, 1937, 82, 2117, 2305, 1047, 2501, 577, 529, 2917, 1451, 3137, 721, 3365, 3601, 3845, 244, 4097, 99, 1945, 4625, 530]

cp's OEIS Frontend

A256517 Let c be the n-th composite number. Then a(n) is the smallest base b > 1 such that b^(c-1) == 1 (mod c^2), i.e., such that c is a 'Wieferich pseudoprime'.

Table of values

List of values