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 A058473 #14 Aug 11 2024 14:41:33
%S A058473 1,3,43694278824566964251,100990098979999970099500001
%N A058473 Numbers k such that k^2 contains only digits {0,1,9}, not ending with zero.
%H A058473 P. De Geest, <a href="https://www.worldofnumbers.com/threedigits.htm">Index to related sequences</a>
%H A058473 Hisanori Mishima, <a href="http://www.asahi-net.or.jp/~KC2H-MSM/mathland/math02/math0210.htm#019">Sporadic tridigital solutions</a>
%H A058473 Zhao Hui Du, <a href="https://bbs.emath.ac.cn/forum.php?mod=redirect&goto=findpost&ptid=19296&pid=99358">Chinese BBS with updated data</a>
%Y A058473 Cf. A058474.
%K A058473 nonn,base,hard,more
%O A058473 1,2
%A A058473 _Patrick De Geest_, Nov 15 2000
%E A058473 a(4) from _Zhao Hui Du_, Feb 28 2024