A128401 - cp's OEIS frontend

A128401 Numbers k such that k^2 divides 21^k-1.

n	a(n)
1	1
2	2
3	4
4	5
5	10
6	20
7	22
8	44
9	52
10	68
11	110
12	220
13	260
14	340
15	506
16	572
17	748
18	820
19	884
20	1012
21	2530
22	2756
23	2860
24	3740
25	3916
26	4108
27	4420
28	5060
29	9020
30	9724
31	10660
32	13156
33	13780
34	13940
35	17204
36	19580
37	20540
38	23782
39	29084
40	30316
41	34060
42	45188
43	46852
44	47564

[1, 2, 4, 5, 10, 20, 22, 44, 52, 68, 110, 220, 260, 340, 506, 572, 748, 820, 884, 1012, 2530, 2756, 2860, 3740, 3916, 4108, 4420, 5060, 9020, 9724, 10660, 13156, 13780, 13940, 17204, 19580, 20540, 23782, 29084, 30316, 34060, 45188, 46852, 47564]

cp's OEIS Frontend

A128401 Numbers k such that k^2 divides 21^k-1.

Table of values

List of values