OFFSET
0,2
COMMENTS
If p is prime, then a(p-1)==2 mod p. At least up to n=251, there is only one nonprime n for which a(n-1)==2 mod n. It is n=18 for which a(18-1)=48080==2(mod 18).
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev and Peter J. C. Moses, Dec 31 2011
STATUS
approved