OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..5000
EXAMPLE
a(9) = 15 is a squarefree number, 1 and 5 are also squarefree numbers.
MATHEMATICA
With[{sf={1, 2, 3, 5, 6, 7}}, Flatten[Table[Select[FromDigits/@ Tuples[ sf, n], SquareFreeQ], {n, 3}]]] (* Harvey P. Dale, Aug 09 2014 *)
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Amarnath Murthy, Jun 16 2001
EXTENSIONS
More terms from Reiner Martin, Jul 20 2001
STATUS
approved