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 A033032 #14 Dec 24 2022 14:40:37
%S A033032 1,3,5,7,9,11,19,21,23,31,33,35,43,45,47,55,57,59,67,69,71,115,117,
%T A033032 119,127,129,131,139,141,143,187,189,191,199,201,203,211,213,215,259,
%U A033032 261,263,271,273,275,283,285,287,331,333,335,343
%N A033032 Numbers all of whose base 6 digits are odd.
%H A033032 Robert Israel, <a href="/A033032/b033032.txt">Table of n, a(n) for n = 1..10000</a>
%F A033032 If (3^d-1)/2 <= n < (3^(d+1)-1)/2, then a(n+3^d) = a(n) + 6^n, a(n+2*3^d) = a(n) + 2*6^n, and a(n+3^(d+1)) = a(n) + 5*6^n. - _Robert Israel_, Aug 16 2018
%p A033032 g:= proc(t,d) local L;
%p A033032 L:= convert(3^d+t,base,3);
%p A033032 add((2*L[i]+1)*6^(i-1),i=1..d);
%p A033032 end proc:
%p A033032 seq(seq(g(t,d),t=0..3^d-1),d=1..4); # _Robert Israel_, Aug 16 2018
%t A033032 Table[FromDigits[#,6]&/@Tuples[{1,3,5},n],{n,4}]//Flatten (* _Harvey P. Dale_, Dec 24 2022 *)
%o A033032 (PARI) isok(n) = (n) && (#select(x->((x%2)==0), digits(n, 6)) == 0); \\ _Michel Marcus_, Aug 17 2018
%K A033032 nonn,base
%O A033032 1,2
%A A033032 _Clark Kimberling_