login
This site is supported by donations to The OEIS Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A188341 Numbers having no 0's and not more than one 1 in their representation in base 3. 8
1, 2, 5, 7, 8, 17, 23, 25, 26, 53, 71, 77, 79, 80, 161, 215, 233, 239, 241, 242, 485, 647, 701, 719, 725, 727, 728, 1457, 1943, 2105, 2159, 2177, 2183, 2185, 2186, 4373, 5831, 6317, 6479, 6533, 6551, 6557, 6559, 6560, 13121, 17495, 18953 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..1000

V. Shevelev, Binomial Coefficient Predictors, Journal of Integer Sequences, Vol. 14 (2011), Article 11.2.8

MAPLE

a:= proc(n) option remember; local i, l, m, t;

      m:= `if`(n=1, 0, a(n-1));

      l:= NULL;

      for t while m>0 do l:= l, irem(m, 3, 'm') od;

      l:= array([l, 0]);

      for i while l[i]=2 do od;

      if l[i]=0 then l[i]:= 1

                else l[i]:= 2;

                     if i>1 then l[i-1]:= 1 fi

      fi;

      add(l[i] *3^(i-1), i=1..t)

    end:

seq(a(n), n=1..100);  # Alois P. Heinz, Apr 02 2011

MATHEMATICA

okQ[n_]:=DigitCount[n, 3, 0]==0&&DigitCount[n, 3, 1]<2; Select[Range[20000], okQ]  (* Harvey P. Dale, Apr 16 2011 *)

CROSSREFS

Cf. A062756, A077267.

Sequence in context: A005624 A275410 A139481 * A238364 A227445 A216968

Adjacent sequences:  A188338 A188339 A188340 * A188342 A188343 A188344

KEYWORD

nonn,base

AUTHOR

Vladimir Shevelev, Apr 02 2011

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 7 03:00 EST 2019. Contains 329836 sequences. (Running on oeis4.)