OFFSET
0,11
EXAMPLE
a(169) = 6 the squares obtained by using the digits are 1,9,16, 169, 196, 961.
MATHEMATICA
Table[Length[Select[Union[Drop[FromDigits/@Flatten[Permutations/@ Subsets[IntegerDigits[n]], 1], 1]], IntegerQ[Sqrt[#]] &]], {n, 0, 104}] (* Jayanta Basu, May 17 2013 *)
CROSSREFS
KEYWORD
base,nonn,easy
AUTHOR
Amarnath Murthy, Jun 29 2001
EXTENSIONS
Corrected and extended by Larry Reeves (larryr(AT)acm.org) and Dean Hickerson, Jul 02 2001
STATUS
approved