OFFSET
1,2
COMMENTS
Also, the odd solutions to 2^(n-6) == 1 (mod n). The only even solution is n=6.
For all m, 2^A033981(m)-1 belongs to this sequence.
LINKS
Max Alekseyev, Table of n, a(n) for n = 1..102 (all terms below 10^14)
MATHEMATICA
m = 64; Join[Select[Range[1, m, 2], Divisible[2^# - m, #] &],
Select[Range[m + 1, 10^6, 2], PowerMod[2, #, #] == m &]] (* Robert Price, Oct 08 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Max Alekseyev, Aug 17 2012
STATUS
approved