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 A053950 #19 Mar 09 2024 20:15:22
%S A053950 2,88,6888,6912,7588,68962,6674412,2749137588,7466242412,
%T A053950 8629863583949388,27341447393189418631675507588
%N A053950 Numbers k such that k^2 contains only digits {4,5,7}.
%H A053950 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 A053950 Patrick De Geest, <a href="http://www.worldofnumbers.com/threedigits.htm">Squares containing at most three distinct digits, Index entries for related sequences</a>
%H A053950 H. Mishima, <a href="http://www.asahi-net.or.jp/~KC2H-MSM/mathland/math02/math0210.htm#457">Sporadic tridigital solutions</a>
%Y A053950 Cf. A053951.
%K A053950 nonn,base,more
%O A053950 1,1
%A A053950 _Patrick De Geest_, Mar 15 2000
%E A053950 More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 04 2005
%E A053950 One more term from Mishima's webpage added by _Max Alekseyev_, Jan 28 2012
%E A053950 a(11) from _Zhao Hui Du_, Mar 09 2024