OFFSET
1,2
MATHEMATICA
ntb4Q[n_]:=Module[{d=DeleteCases[DigitCount[n, 4], 0]}, Length[d] == Length[ Union[d]]]; Select[Range[200], ntb4Q] (* Harvey P. Dale, Jun 22 2013 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
STATUS
approved