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 A053915 #16 Aug 11 2024 14:41:32
%S A053915 1,9,81,11881,19881,111999889,1199998881,1981191998999889,
%T A053915 11181188899981881,889111189818189198888889,
%U A053915 18891818199881191889889889,8819999189981919818818919999881
%N A053915 Squares composed of digits {1,8,9}.
%H A053915 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 A053915 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 A053915 H. Mishima, <a href="http://www.asahi-net.or.jp/~KC2H-MSM/mathland/math02/math0210.htm#189">Sporadic tridigital solutions</a>
%F A053915 a(n) = A053914(n)^2.
%Y A053915 Cf. A053914.
%K A053915 nonn,base,more
%O A053915 1,2
%A A053915 _Patrick De Geest_, Mar 15 2000
%E A053915 One more term from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 14 2005
%E A053915 One more term from _Jon E. Schoenfield_, Sep 03 2006
%E A053915 One more term from Mishima's webpage added by _Max Alekseyev_, Jan 28 2012