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%I #13 Oct 21 2024 15:34:33
%S 0,1,2,2,3,4,4,5,6,6,6,6,6,7,8,8,9,10,10,10,10,10,11,12,12,13,14,14,
%T 14,14,14,14,14,14,14,14,14,14,14,14,15,16,16,17,18,18,18,18,18,19,20,
%U 20,21,22,22,22,22,22,22,22,22,22,22,22,22,22,22,23,24,24,25,26,26,26,26
%N Number of numbers <= n having no 0 in their ternary representation.
%C a(n) + A081607(n) = n+1.
%H Winston de Greef, <a href="/A081608/b081608.txt">Table of n, a(n) for n = 0..16383</a>
%t Accumulate[Table[If[DigitCount[n,3,0]==0,1,0],{n,0,80}]] (* _Harvey P. Dale_, Oct 21 2024 *)
%o (PARI) first(n)=my(s,t); vector(n,k, t=Set(digits(k,3)); s+=!!t[1]) \\ _Charles R Greathouse IV_, Sep 02 2015
%Y Cf. A007089, A077267, A061392, A081611.
%K nonn
%O 0,3
%A _Reinhard Zumkeller_, Mar 23 2003