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 A053951 #17 Mar 10 2024 07:41:08
%S A053951 4,7744,47444544,47775744,57577744,4755757444,44547775545744,
%T A053951 7557757477754457744,55744775754747577744,
%U A053951 74474545477575775744575745574544,747554745554544455555455747745774457774554454557445577744
%N A053951 Squares composed of digits {4,5,7}.
%H A053951 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 A053951 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 A053951 H. Mishima, <a href="http://www.asahi-net.or.jp/~KC2H-MSM/mathland/math02/math0210.htm#457">Sporadic tridigital solutions</a>
%F A053951 a(n) = A053950(n)^2.
%Y A053951 Cf. A053950.
%K A053951 nonn,base,more
%O A053951 1,1
%A A053951 _Patrick De Geest_, Mar 15 2000
%E A053951 More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 04 2005
%E A053951 One more term from Mishima's webpage added by _Max Alekseyev_, Jan 28 2012
%E A053951 a(11) from _Zhao Hui Du_, Mar 10 2024