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 A231933 #7 Nov 16 2013 14:14:33
%S A231933 0,10,1,9,81,11,2,18,82,20,3,12,28,84,27,90,30,4,13,37,85,36,94,22,38,
%T A231933 92,19,83,99,163,171,729,86,14,5,23,47,95,32,48,93,21,29,100,24,6,15,
%U A231933 55,87,54,96,33,57,109,31,39,112,120,256,280,336,352,732,91,16,7,25
%N A231933 Terms of A231932 written in base 10: the binary expansions of a(n) and a(n+1) taken together can be rearranged to form a palindrome.
%C A231933 See A231931 for precise definition.
%C A231933 This is a permutation of the nonnegative integers - see the Comments in A228407 for the proof.
%t A231933 a[0] = 0; a[n_] := a[n] = Block[{k = 1, idm = IntegerDigits[ a[n - 1], 9], t = a@# & /@ Range[n - 1]}, Label[ start]; While[ MemberQ[t, k], k++]; While[ Select[ Permutations[ Join[ idm, IntegerDigits[k, 9]]], #[[1]] != 0 && # == Reverse@# &] == {}, k++; Goto[ start]]; k]; s = Array[a, 60, 0]
%Y A231933 Cf. A230892, A231921, A231923, A231925, A231927, A231929, A231931, A228407, A231932.
%K A231933 nonn,base,easy
%O A231933 0,2
%A A231933 _N. J. A. Sloane_ and _Robert G. Wilson v_, Nov 15 2013