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 A053912 #9 Aug 11 2024 14:41:32
%S A053912 1,9,109,280859,105769141,279067891
%N A053912 Numbers k such that k^2 contains only digits {1,7,8}.
%H A053912 P. De Geest, <a href="https://www.worldofnumbers.com/threedigits.htm">Squares containing at most three distinct digits, Index entries for related sequences</a>
%Y A053912 Cf. A053913.
%K A053912 nonn,base,more
%O A053912 1,2
%A A053912 _Patrick De Geest_, Mar 15 2000