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 A061231 #7 Jun 05 2016 14:42:55
%S A061231 10,21,32,40,43,51,54,62,65,73,76,84,87,90,95,98,1030,1100,1140,1210,
%T A061231 1250,1320,1360,1430,1470,1540,1580,1650,1690,1760,1870,1980,2031,
%U A061231 2101,2141,2211,2251,2321,2361,2431,2471,2541,2581,2651,2691,2761,2871,2981
%N A061231 n - the reversal of n is a nonzero square.
%H A061231 Harvey P. Dale, <a href="/A061231/b061231.txt">Table of n, a(n) for n = 0..1000</a>
%e A061231 a(4) = 40 as 40 - 4 = 36 = 6^2; a(9)= 65 as 65- 56 = 9 = 3^2.
%t A061231 nzsQ[n_]:=Module[{c=n-IntegerReverse[n]},c!=0&&IntegerQ[Sqrt[c]]]; Select[ Range[3000],nzsQ] (* The program uses the IntegerReverse function from Mathematica version 10 *) (* _Harvey P. Dale_, Jun 05 2016 *)
%Y A061231 Cf. A061230.
%K A061231 nonn,base
%O A061231 0,1
%A A061231 _Amarnath Murthy_, Apr 23 2001
%E A061231 More terms from _Patrick De Geest_, May 28 2001