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 A115689 #9 Aug 08 2020 15:17:46
%S A115689 1,4,9,100,121,144,169,400,441,484,675,676,900,961,1000,1089,1800,
%T A115689 4000,9000,9801,10000,10201,10404,10609,12100,12321,12544,12769,14400,
%U A115689 14641,14884,16900,18000,18252,40000,40401,40804,44100,44521,44944
%N A115689 Powerful(1) numbers (A001694) whose digit reversal is a square.
%H A115689 Harvey P. Dale, <a href="/A115689/b115689.txt">Table of n, a(n) for n = 1..160</a>
%H A115689 <a href="/index/Pow#powerful">Index entries for sequences related to powerful numbers</a>
%e A115689 18252=2^2*3^3*13^2 is powerful and 25281=159^2.
%t A115689 Join[{1},Select[Range[50000],Min[FactorInteger[#][[All,2]]]>1&& IntegerQ[ Sqrt[ IntegerReverse[#]]]&]] (* _Harvey P. Dale_, Aug 08 2020 *)
%Y A115689 Cf. A001694, A115690.
%K A115689 nonn,base
%O A115689 1,2
%A A115689 _Giovanni Resta_, Jan 31 2006