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 A247263 #10 Sep 14 2014 00:22:08 %S A247263 375,2371875, %T A247263 6816208478590683385931482169914619837072677910327911376953125, %U A247263 140221743281593822163509288486586064542459780568606220185756683349609375,818488127823449514709977488133381451695186814276894438080489635467529296875 %N A247263 Positive numbers not divisible by 10 whose squares remain squares when prefixed with 1000. %H A247263 Chai Wah Wu, <a href="/A247263/b247263.txt">Table of n, a(n) for n = 1..53</a> %e A247263 375^2 = 140625 and 1000140625 is square. %o A247263 (PARI) %o A247263 for(n=1,10^20,if(n^2%100&&issquare(10^(#Str(n^2)+3)+n^2),print1(n^2,", "))) \\ _Derek Orr_, Sep 13 2014 %Y A247263 Cf. A242268, A247261, A247262, A247264. %K A247263 nonn,base %O A247263 1,1 %A A247263 _Chai Wah Wu_, Sep 11 2014