%I #8 Jan 24 2021 13:09:27
%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
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