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 A247261 #14 Jun 02 2025 10:14:54 %S A247261 5625,50625,62187890625,453097265625,684420119384765625, %T A247261 4030118984619140625,7501588188366851806640625, %U A247261 35596572549171295166015625,81913198262420037174224853515625,311932283242100929355621337890625,891378408151941675529539585113525390625 %N A247261 Positive squares not ending in 00 that remain squares when prefixed with 10. %H A247261 Chai Wah Wu, <a href="/A247261/b247261.txt">Table of n, a(n) for n = 1..263</a> %e A247261 5625 and 105625 are both squares. %o A247261 (PARI) %o A247261 for(n=1,10^7,if(n^2%100&&issquare(10^(#Str(n^2)+1)+n^2),print1(n^2,", "))) \\ _Derek Orr_, Sep 13 2014 %Y A247261 Cf. A242268, A247262, A247263, A247264. %K A247261 nonn,base %O A247261 1,1 %A A247261 _Chai Wah Wu_, Sep 10 2014