A215611 - OEIS

A215611

Odd integers n such that 2^n == 2^8 (mod n).

%I #15 Oct 12 2018 14:57:17

%S 1,127,3473,19313,30353,226703,230777,345023,929783,1790159,1878073,

%T 2569337,3441743,4213511,8026103,9770153,19139183,24261623,30652223,

%U 35482433,38044223,40642103,55015793,65046479,67411121,69601193,119611073

%N Odd integers n such that 2^n == 2^8 (mod n).

%C Also, the odd solutions to 2^(n-8) == 1 (mod n). The only even solution is n=8.

%C For all m, 2^A051447(m)-1 belongs to this sequence.

%H Max Alekseyev, <a href="/A215611/b215611.txt">Table of n, a(n) for n = 1..859</a> (all terms below 10^14)

%t m = 2^8; Join[Select[Range[1, m, 2], Divisible[2^# - m, #] &],

%t Select[Range[m + 1, 10^6, 2], PowerMod[2, #, #] == m &]] (* _Robert Price_, Oct 12 2018 *)

%Y The odd terms of A015929.

%Y Cf. A051447, A033984, A173572, A215610, A215612, A215613.

%K nonn

%O 1,2

%A _Max Alekseyev_, Aug 17 2012