OFFSET
1,1
COMMENTS
Not known to be infinite. Also, it is not known if every integer is the sum of 4 or fewer terms of A277238, although this is true up to 2^20.
MATHEMATICA
Take[#, 66] &@ Complement[Range@ Max@ #, #] &@ Union@ Map[Total, Rest@ Tuples[{0}~Join~#, 3]] &@ Prepend[Select[Range[10^3], If[OddQ@ Length@ # && Take[#, {Ceiling[Length[#]/2]}] == {0}, False, Union[Take[#, Floor[Length[#]/2]] + Reverse@ Take[#, -Floor[Length[#]/2]]] == {1}] &@ IntegerDigits[#, 2] &], 1] (* Michael De Vlieger, Nov 25 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Jeffrey Shallit, Nov 24 2016
STATUS
approved