OFFSET
1,2
COMMENTS
LINKS
MATHEMATICA
Nest[Append[#, If[#[[-1]] == #[[-2]] + 1, 2 #[[-1]], Min[Complement[Range[Max[#] + 1], #]]]] &, {1, 2}, 69] (* Ivan Neretin, Sep 08 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jan 15 2005
STATUS
approved