OFFSET
1,1
COMMENTS
MATHEMATICA
Sort[FromDigits/@Flatten[Table[Permutations[PadRight[{}, 2n, {1, 7}]], {n, 3}], 1]] (* Harvey P. Dale, Aug 30 2016 *)
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Jonathan Vos Post, Jul 20 2012
STATUS
approved