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 A145848 #14 Aug 09 2015 23:19:38
%S A145848 49,1681,144400,225625,256036,324900,576081,24019801,1299602500,
%T A145848 1587624025,2371690000,2496401296,2528178961,2924105625,3132976729,
%U A145848 5198410000,5616902916,6350496100,8122515625,9985605184,249001998001
%N A145848 Squares with an even number of digits, where the first half is a square and the second half is a nonzero square.
%H A145848 Jon E. Schoenfield, <a href="/A145848/b145848.txt">Table of n, a(n) for n = 1..221</a>
%H A145848 <a href="http://blog.tanyakhovanova.com/?p=66">Four Puzzles for the Price of One</a> - from the 1997 USSR math olympiad
%e A145848 1681 is a square, where the first two digits form a square and the last two digits form a nonzero square.
%t A145848 Flatten[Table[ Select[Flatten[ Table[FromDigits[ Join[IntegerDigits[i^2], PadLeft[IntegerDigits[j^2], n]]], {i, Floor[Sqrt[10^(n - 1)]], Floor[Sqrt[10^n - 1]]}, {j, Floor[Sqrt[10^n - 1]]}]], IntegerQ[Sqrt[ # ]] &], {n, 5}]]
%K A145848 nonn,base
%O A145848 1,1
%A A145848 _Tanya Khovanova_, Oct 21 2008
%E A145848 More terms from _Jon E. Schoenfield_, Nov 17 2008
%E A145848 Edited by _Charles R Greathouse IV_, Aug 02 2010