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 A053939 #16 Aug 11 2024 14:41:32
%S A053939 4,36,64,3364,4443664,443433464464,466363336464,43346343434436,
%T A053939 46443434463364,3436643466443664,33663346434644644,
%U A053939 6344433646663343363344,444336446434444344644644,4333643333666334466333636,4464644636363464333646646666664464,44444633333463334436443663666646446336
%N A053939 Squares composed of digits {3,4,6}.
%H A053939 P. De Geest, <a href="https://www.worldofnumbers.com/threedigits.htm">Squares containing at most three distinct digits, Index entries for related sequences</a>
%H A053939 Author?, <a href="http://web.archive.org/web/20080708203024/http://blue.kakiko.com/mmrmmr/htm/eqtn06.html">Source</a> (<a href="http://web.archive.org/web/20060426155831/http://blue.kakiko.com/mmrmmr/txt/eqtn06.txt">txt</a>)
%H A053939 Hisanori Mishima, <a href="http://www.asahi-net.or.jp/~KC2H-MSM/mathland/math02/math0210.htm#346">Sporadic tridigital solutions</a>
%F A053939 a(n) = A053938(n)^2.
%Y A053939 Cf. A053938.
%K A053939 nonn,base
%O A053939 1,1
%A A053939 _Patrick De Geest_, Mar 15 2000
%E A053939 More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 03 2005
%E A053939 a(14)-a(16) from Mishima's website, added by _Max Alekseyev_, Nov 30 2017