A030439 a(n+1) = smallest number not containing any digits of a(n), working in base 3.

0, 1, 2, 3, 8, 9, 26, 27, 80, 81, 242, 243, 728, 729, 2186, 2187, 6560, 6561, 19682, 19683, 59048, 59049, 177146, 177147, 531440, 531441, 1594322, 1594323, 4782968, 4782969, 14348906, 14348907, 43046720, 43046721, 129140162, 129140163, 387420488, 387420489

Offset

0,3

Links

Table of n, a(n) for n=0..37.

Index entries for linear recurrences with constant coefficients, signature (0, 4, 0, -3).

Formula

3^i-1 then 3^i.

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

a(n) = 3^floor(n/2) -1 +(n mod 2). - Alois P. Heinz, Sep 14 2014

Prog

(PARI) a(n)=([0, 1, 0, 0; 0, 0, 1, 0; 0, 0, 0, 1; -3, 0, 4, 0]^n*[0; 1; 2; 3])[1, 1] \\ Charles R Greathouse IV, Jun 02 2026

Crossrefs

Cf. A030283.

Bisections give: A024023, A000244.

Sequence in context: A163168 A085453 A271394 * A119386 A162219 A140484

Adjacent sequences: A030436 A030437 A030438 * A030440 A030441 A030442

Keyword

nonn,base,easy

Author

N. J. A. Sloane

Status

approved