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 A118735 #14 Jul 11 2025 15:37:18
%S A118735 0,4,5,10,16,18,20,22,25,27,30,31,34,35,39,48,52,53,59,62,63,66,68,69,
%T A118735 81,87,89,92,99,100,101,105,108,114,118,119,121,127,131,133,141,145,
%U A118735 146,150,153,158,159,160,165,167,169,175,186,188,191,196,197,201,202,203
%N A118735 Numbers k such that 2^k and 3^k have odd digit sum.
%H A118735 Harvey P. Dale, <a href="/A118735/b118735.txt">Table of n, a(n) for n = 1..1000</a>
%t A118735 Select[Range[0, 206], And @@ ((Mod[ Plus @@ IntegerDigits[ # ], 2] == 1 &) /@ {2^#, 3^#}) &] (* _Ray Chandler_, Jun 10 2006 *)
%t A118735 odsQ[n_]:=AllTrue[Total[IntegerDigits[#]]&/@{2^n,3^n},OddQ]; Select[ Range[ 0,250],odsQ] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jun 05 2021 *)
%Y A118735 Cf. Intersection of A118731 and A118732.
%K A118735 base,nonn
%O A118735 1,2
%A A118735 _Zak Seidov_, May 22 2006
%E A118735 Extended by _Ray Chandler_, Jun 10 2006