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 A053885 #12 Aug 11 2024 14:41:32
%S A053885 1,121,2217121,21127711127121,17177711172112177722222121,
%T A053885 17117772217211221211117217772227121
%N A053885 Squares composed of digits {1,2,7}.
%C A053885 The least significant, i.e., rightmost, digit must be 1. - _Harvey P. Dale_, Jan 05 2022
%H A053885 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 A053885 Hisanori Mishima, <a href="http://www.asahi-net.or.jp/~KC2H-MSM/mathland/math02/math0210.htm#127">Sporadic tridigital solutions</a>
%Y A053885 Cf. A053884.
%K A053885 nonn,base,more
%O A053885 1,2
%A A053885 _Patrick De Geest_, Mar 15 2000
%E A053885 One more term from _Jon E. Schoenfield_, Sep 03 2006
%E A053885 One more term from Herman Jamke (hermanjamke(AT)fastmail.fm), Dec 23 2007