This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A023733 #32 Apr 14 2025 05:33:12
%S A023733 0,1,2,4,5,6,7,9,10,11,12,14,20,21,22,24,25,26,27,29,30,31,32,34,35,
%T A023733 36,37,39,45,46,47,49,50,51,52,54,55,56,57,59,60,61,62,64,70,71,72,74,
%U A023733 100,101,102,104,105,106,107,109,110,111,112,114
%N A023733 Numbers with no 3's in base-5 expansion.
%H A023733 Nathaniel Johnston, <a href="/A023733/b023733.txt">Table of n, a(n) for n = 1..10000</a>
%H A023733 Robert Baillie and Thomas Schmelzer, <a href="https://library.wolfram.com/infocenter/MathSource/7166/">Summing Kempner's Curious (Slowly-Convergent) Series</a>, Mathematica Notebook kempnerSums.nb, Wolfram Library Archive, 2008.
%H A023733 <a href="/index/Ar#5-automatic">Index entries for 5-automatic sequences</a>.
%F A023733 Sum_{n>=2} 1/a(n) = 7.2918685472993284072384543509909968409572571215800451577936556651148540560895813691253670323741759722063... (calculated using Baillie and Schmelzer's kempnerSums.nb, see Links). - _Amiram Eldar_, Apr 14 2025
%e A023733 14 in base 5 is 24, which contains no 3's, so 14 is in the sequence.
%e A023733 15 in base 5 is 30, so 15 is not in the sequence.
%p A023733 seq(`if`(numboccur(3,convert(n,base,5))=0,n,NULL),n=0..127); # _Nathaniel Johnston_, Jun 27 2011
%t A023733 Select[Range[0, 124], Count[IntegerDigits[#, 5], 3] == 0 &]
%t A023733 Select[Range[0,200],DigitCount[#,5,3]==0&] (* _Harvey P. Dale_, Jul 29 2024 *)
%o A023733 (PARI) is(n)=while(n>3, if(n%5==3, return(0)); n\=5); 1 \\ _Charles R Greathouse IV_, Feb 12 2017
%o A023733 (Scala) (0 to 124).filter(Integer.toString(_, 5).indexOf("3") == -1) // _Alonso del Arte_, Feb 05 2019
%Y A023733 Cf. A020654, A023721, A023725, A023729.
%K A023733 nonn,base,easy
%O A023733 1,3
%A A023733 _Olivier Gérard_