%I #16 Jul 04 2024 13:20:38

%S 0,1,2,3,8,9,26,27,80,81,242,243,728,729,2186,2187,6560,6561,19682,

%T 19683,59048,59049,177146,177147,531440,531441,1594322,1594323,

%U 4782968,4782969,14348906,14348907,43046720,43046721,129140162,129140163,387420488,387420489

%N a(n+1) = smallest number not containing any digits of a(n), working in base 3.

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0, 4, 0, -3).

%F 3^i-1 then 3^i.

%F a(n) = 4*a(n-2)-3*a(n-4); g.f.: -x*(x^2-2*x-1) / ((x-1)*(x+1)*(3*x^2-1)). - _Colin Barker_, Sep 13 2014

%F a(n) = 3^floor(n/2) -1 +(n mod 2). - _Alois P. Heinz_, Sep 14 2014

%Y Cf. A030283.

%Y Bisections give: A024023, A000244.

%K nonn,base

%O 0,3

%A _N. J. A. Sloane_.