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 A227548 #6 Aug 01 2013 05:01:02
%S A227548 1,50,56,60,90,4900,5100,7500,7600,9900,12500,499000,501000,624000,
%T A227548 625000,749000,751000,875000,999000,1249000,13427757,49990000,
%U A227548 50010000,56250000,62490000
%N A227548 Numbers n such that n^3 has n as its middle digits.
%e A227548 a(6)=4900 because 4900^3 = 117649000000 has 4900 as its middle digits.
%t A227548 Do[If[StringPosition[ToString[n^3], ToString[n]][[1, 1]] == (Ceiling[Log[10, n^3]] - Ceiling[Log[10, n]]) / 2 + 1, Print[n]], {n, 0, 10^8}]
%Y A227548 Cf. A062118.
%K A227548 nonn,base
%O A227548 1,2
%A A227548 _Vincenzo Librandi_, Jul 30 2013