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 A167038 #16 Mar 15 2024 02:24:09
%S A167038 9,225,900,2025,22500,90000,202500,950625,2250000,9000000,20250000,
%T A167038 85100625,95062500,225000000,900000000,2025000000,2487515625,
%U A167038 8510062500,9506250000,18123890625,22500000000,90000000000,202500000000,248751562500,851006250000
%N A167038 Squares that remain squares when prefixed with a 4.
%H A167038 Chai Wah Wu, <a href="/A167038/b167038.txt">Table of n, a(n) for n = 1..1000</a>
%e A167038 9 = 3^2 is a square and becomes the square 49 = 7^2 if a 4 is attached in front of its decimal representation.
%t A167038 Select[Range[450000]^2,IntegerQ[Sqrt[FromDigits[Join[{4}, IntegerDigits[ #]]]]]&] (* _Harvey P. Dale_, Aug 05 2014 *)
%K A167038 nonn,base
%O A167038 1,1
%A A167038 _Claudio Meller_, Oct 27 2009
%E A167038 Keyword:base added by _R. J. Mathar_, Oct 28 2009
%E A167038 More terms from _Chai Wah Wu_, Sep 11 2014