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 A053975 #12 Sep 02 2024 01:20:40
%S A053975 9,6889,69696,698896,9696996,66699889,9669968896,669668898889,
%T A053975 686688996889,989698666896,86668968686689,969896699696888896,
%U A053975 6869996688989986989889,898889698869898988888689,969986886696696688968996
%N A053975 Squares composed of digits {6,8,9}.
%H A053975 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 A053975 Hisanori Mishima, <a href="http://www.asahi-net.or.jp/~KC2H-MSM/mathland/math02/math0210.htm#689">Sporadic tridigital solutions</a>
%F A053975 a(n) = A053974(n)^2.
%Y A053975 Cf. A053974.
%K A053975 nonn,base
%O A053975 1,1
%A A053975 _Patrick De Geest_, Mar 15 2000
%E A053975 More terms from _Gareth McCaughan_, Jun 11 2004