OFFSET
1,1
MATHEMATICA
Select[Flatten[Table[FromDigits/@Tuples[{1, 4, 8, 9}, n], {n, 2, 4}]], SquareFreeQ] (* Harvey P. Dale, Oct 10 2013 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Nov 16 2002
EXTENSIONS
Corrected and extended by David Garber, Nov 19 2002
STATUS
approved