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 A033033 #16 Sep 08 2022 08:44:51
%S A033033 1,3,5,8,10,12,22,24,26,36,38,40,57,59,61,71,73,75,85,87,89,155,157,
%T A033033 159,169,171,173,183,185,187,253,255,257,267,269,271,281,283,285,400,
%U A033033 402,404,414,416,418,428,430,432,498,500,502,512
%N A033033 Numbers all of whose base 7 digits are odd.
%H A033033 David A. Corneth, <a href="/A033033/b033033.txt">Table of n, a(n) for n = 1..10000</a>
%e A033033 38 in base 7 is 53_7. All the digits of 38 in base 7; 5 and 3; are odd. So 38 is in the sequence. - _David A. Corneth_, Aug 24 2019
%t A033033 Select[Range[600],AllTrue[IntegerDigits[#,7],OddQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Sep 28 2014 *)
%o A033033 (PARI) is(n) = {my(d = Set(digits(n, 7))); for(i = 1, #d, if(d[i]%2 == 0, return(0))); 1} \\ _David A. Corneth_, Aug 24 2019
%o A033033 (Magma) [m:m in [1..600]| Intseq(m,7) subset {1,3,5}]; // _Marius A. Burtea_, Aug 24 2019
%Y A033033 Cf. A007093, A014261.
%K A033033 nonn,easy,base
%O A033033 1,2
%A A033033 _Clark Kimberling_