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