OFFSET
1,2
COMMENTS
Subsequence of A014946.
MATHEMATICA
Select[Range[20000], IntegerQ[(PowerMod[6, #, #^2 ]-1)/#^2 ]&]
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
Alexander Adamchuk, Jan 05 2007
EXTENSIONS
Two more terms from Max Alekseyev, May 05 2010
STATUS
approved