%I

%S 0,1,2,3,4,5,6,7,9

%N 3^n uses only distinct decimal digits.

%C There are exactly 9 such n's that 3^n uses only distinct digits (in base 10).

%e 9 is (the last!) term because 3^9=19683 uses only distinct digits.

%t Select[Range[0,10],Max[DigitCount[3^#]]<2&] (* _Harvey P. Dale_, Jan 24 2021 *)

%K fini,nonn,full,base

%O 1,3

%A _Zak Seidov_, Jul 01 2003