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A188341 Numbers having no 0's and not more than one 1 in their representation in base 3.

%I A188341 #30 Nov 14 2014 07:23:55
%S A188341 1,2,5,7,8,17,23,25,26,53,71,77,79,80,161,215,233,239,241,242,485,647,
%T A188341 701,719,725,727,728,1457,1943,2105,2159,2177,2183,2185,2186,4373,
%U A188341 5831,6317,6479,6533,6551,6557,6559,6560,13121,17495,18953
%N A188341 Numbers having no 0's and not more than one 1 in their representation in base 3.
%H A188341 Alois P. Heinz, <a href="/A188341/b188341.txt">Table of n, a(n) for n = 1..1000</a>
%H A188341 V. Shevelev, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL14/Shevelev/shevelev14.html">Binomial Coefficient Predictors</a>, Journal of Integer Sequences, Vol. 14 (2011), Article 11.2.8
%p A188341 a:= proc(n) option remember; local i, l, m, t;
%p A188341       m:= `if`(n=1, 0, a(n-1));
%p A188341       l:= NULL;
%p A188341       for t while m>0 do l:= l, irem(m, 3, 'm') od;
%p A188341       l:= array([l, 0]);
%p A188341       for i while l[i]=2 do od;
%p A188341       if l[i]=0 then l[i]:= 1
%p A188341                 else l[i]:= 2;
%p A188341                      if i>1 then l[i-1]:= 1 fi
%p A188341       fi;
%p A188341       add(l[i] *3^(i-1), i=1..t)
%p A188341     end:
%p A188341 seq(a(n), n=1..100);  # _Alois P. Heinz_, Apr 02 2011
%t A188341 okQ[n_]:=DigitCount[n,3,0]==0&&DigitCount[n,3,1]<2; Select[Range[20000], okQ]  (* _Harvey P. Dale_, Apr 16 2011 *)
%Y A188341 Cf. A062756, A077267.
%K A188341 nonn,base
%O A188341 1,2
%A A188341 _Vladimir Shevelev_, Apr 02 2011