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 A084011 #17 Jan 10 2017 19:43:01
%S A084011 1,2,3,4,5,6,7,8,9,1,11,21,31,41,51,61,71,81,82,2,12,22,32,42,52,62,
%T A084011 72,73,83,3,13,23,33,43,53,63,64,74,84,4,14,24,34,44,54,55,65,75,85,5,
%U A084011 15,25,35,45,46,56,66,76,86,6,16,26,36,37,47,57,67,77,87,7,17,27,28,38,48,58
%N A084011 Digit reversal of 11*n, divided by 11.
%H A084011 Indranil Ghosh, <a href="/A084011/b084011.txt">Table of n, a(n) for n = 1..9999</a>
%F A084011 a(n) = A004086(11*n)/11. - _Indranil Ghosh_, Jan 10 2017
%e A084011 For n = 13, A004086(13*11)/11 = 341/11 = 31. So, a(13) = 31. - _Indranil Ghosh_, Jan 10 2017
%t A084011 a[n_] := Module[{aux = IntegerDigits[11*n]},Sum[aux[[i]]*10^(i - 1), {i, 1, Length[aux]}]/11]; Table[a[n], {n, 100}] (* _José María Grau Ribas_, Feb 16 2010 *)
%o A084011 (Python)
%o A084011 def A084011(n):
%o A084011 return int(str(11*n)[::-1])/11 # _Indranil Ghosh_, Jan 10 2017
%Y A084011 Cf. A004086, A007091.
%Y A084011 Cf. A039691 (n such that a(n) = A004086(n)).
%K A084011 base,nonn
%O A084011 1,2
%A A084011 _Amarnath Murthy_, May 23 2003