A319505 - cp's OEIS frontend

A319505 Numbers k such that 2^(k*(k+1)/2) == -1 (mod k^2).

n	a(n)
1	1
2	389993
3	476729
4	2927297
5	3048569
6	3862529
7	3914049
8	4755729
9	5077209
10	7460409
11	9009489
12	9314009
13	11066649
14	11981409
15	12928289
16	13342769
17	15371609
18	15574449
19	22975249
20	34429449
21	44876649
22	57046209
23	66358417
24	66963369
25	79552209
26	83006769
27	96783929
28	99127313
29	118462737
30	126209609
31	128566689
32	139745969

[1, 389993, 476729, 2927297, 3048569, 3862529, 3914049, 4755729, 5077209, 7460409, 9009489, 9314009, 11066649, 11981409, 12928289, 13342769, 15371609, 15574449, 22975249, 34429449, 44876649, 57046209, 66358417, 66963369, 79552209, 83006769, 96783929, 99127313, 118462737, 126209609, 128566689, 139745969]

cp's OEIS Frontend

A319505 Numbers k such that 2^(k*(k+1)/2) == -1 (mod k^2).

Table of values

List of values