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 A272215 #20 Jan 27 2020 12:53:07
%S A272215 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,12,22,32,24,52,26,
%T A272215 72,28,92,30,13,32,33,34,35,36,37,38,39,40,14,24,34,44,54,64,74,48,94,
%U A272215 50,15,52,35,54,55,56,57,58,59,60,16,26,36,64,56,66,76,68,96,70,17,72,37,74,57,76,77,78,79,80,18,28,38
%N A272215 a(n) = that number formed by permuting the digits of n which is divisible by the highest power of 2 (in case of a tie, choose the smallest number).
%C A272215 There is no reason to allow permutations that begin with 0, because we can always gain a power of 2 by putting that zero at the other end. - _N. J. A. Sloane_, Apr 23 2016
%H A272215 David A. Corneth, <a href="/A272215/b272215.txt">Table of n, a(n) for n = 1..10000</a>
%e A272215 The numbers obtained by permuting the digits of 1336 are 1336, 1363, 1633, 3136, 3163, 6133, 3316, 3613, 6313, 3361, 3631 and 6331. The highest power of 2 dividing any of these is 2^6, which divides just one of them, 3136, so a(1336) = 3136.
%t A272215 hp2[n_]:=Module[{c={#,IntegerExponent[#,2]}&/@(FromDigits/@ Permutations[ IntegerDigits[ n]]),mx},mx=Max[c[[All,2]]];Min[Select[c,#[[2]]==mx&][[All,1]]]]; Array[hp2,90] (* _Harvey P. Dale_, Jan 27 2020 *)
%Y A272215 Cf. A261370, A272216.
%K A272215 nonn,base,look
%O A272215 1,2
%A A272215 _David A. Corneth_, Apr 22 2016