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 A032912 #17 Oct 13 2023 12:31:07
%S A032912 1,3,6,8,16,18,31,33,41,43,81,83,91,93,156,158,166,168,206,208,216,
%T A032912 218,406,408,416,418,456,458,466,468,781,783,791,793,831,833,841,843,
%U A032912 1031,1033,1041,1043,1081,1083,1091,1093,2031,2033
%N A032912 Numbers whose set of base-5 digits is {1,3}.
%C A032912 Or, Numbers all of whose base-5 digits are odd.
%H A032912 Vincenzo Librandi, <a href="/A032912/b032912.txt">Table of n, a(n) for n = 1..1000</a>
%t A032912 Flatten[Table[FromDigits[#,5]&/@Tuples[{1,3},n],{n,5}]] (* _Vincenzo Librandi_, Jun 01 2012 *)
%o A032912 (Magma) [n: n in [1..2500] | Set(IntegerToSequence(n, 5)) subset {1, 3}]; // _Vincenzo Librandi_, Jun 01 2012
%o A032912 (Python)
%o A032912 def A032912(n): return (int(bin(m:=n+1)[3:],5)<<1) + (5**(m.bit_length()-1)-1>>2) # _Chai Wah Wu_, Oct 13 2023
%Y A032912 Cf. A007091.
%K A032912 nonn,base
%O A032912 1,2
%A A032912 _Clark Kimberling_