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 A029985 #18 Feb 10 2025 19:56:21
%S A029985 0,1,4,16,100,121,400,484,784,1156,3136,6724,7921,12769,23716,26896,
%T A029985 59536,68644,238144,274576,532900,570025,643204,743044,1042441,
%U A029985 1800964,1844164,2131600,4787344,5026564,7203856,7376656,9278116
%N A029985 Squares which are palindromes in base 3.
%H A029985 Chai Wah Wu, <a href="/A029985/b029985.txt">Table of n, a(n) for n = 1..521</a>
%H A029985 Patrick De Geest, <a href="https://www.worldofnumbers.com/nobase10pg2.htm">Palindromic Squares in bases 2 to 17</a>
%H A029985 G. J. Simmons, <a href="/A002778/a002778.pdf">On palindromic squares of non-palindromic numbers</a>, J. Rec. Math., 5 (No. 1, 1972), 11-19. [Annotated scanned copy]
%t A029985 b3pQ[n_]:=Module[{idn3=IntegerDigits[n,3]},idn3==Reverse[idn3]]; Select[ Range[0,3200]^2,b3pQ] (* _Harvey P. Dale_, Aug 07 2011 *)
%Y A029985 Cf. A029984, A263607, A263608; also A002778, A003166.
%K A029985 nonn,base
%O A029985 1,3
%A A029985 _Patrick De Geest_