OFFSET
1,1
COMMENTS
Solutions to 2^x == 1 (mod x-1).
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..300 from Harvey P. Dale)
MATHEMATICA
Join[{2}, Select[Range[2, 64000], PowerMod[2, #, #-1]==1&]] (* Harvey P. Dale, Jun 01 2021 *)
PROG
(PARI) is(k) = !(k % 2) && Mod(2, k-1)^k == 1; \\ Amiram Eldar, Jul 10 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Sep 22 2003
STATUS
approved