OFFSET
1,2
LINKS
T. D. Noe, Table of n, a(n) for n = 1..1000
OEIS Wiki, 2^n mod n
MATHEMATICA
Select[Range[500], PowerMod[2, #, #] == 4 &] (* Alonso del Arte, Jul 07 2011 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Edited and terms 1,2,4 prepended by Max Alekseyev, Jul 29 2011
STATUS
approved