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 A053931 #33 Jul 18 2025 08:34:33
%S A053931 9,29929,69696,929296,9696996,996222969,26629996969,69926926969,
%T A053931 269996262622969,9222222699262629962929,9929662926692269969296,
%U A053931 96296299962926222299669929,2669292996662992629666262969,2699929699222292222296696996,62969966996922666266229669292996
%N A053931 Squares composed of digits {2,6,9}.
%D A053931 Clifford A. Pickover, The Mathematics of Oz, Chapter 9, "Square Overdrive", page 250, Cambridge University Press 2002.
%H A053931 Zhao Hui Du, <a href="/A053931/b053931.txt">Table of n, a(n) for n = 1..18</a>
%H A053931 Joe K. Crump, <a href="https://web.archive.org/web/20100308181731/http://www.immortaltheory.com/NumberTheory/TriDigitalSquares.htm">TriDigital Squares</a>.
%H A053931 Patrick De Geest, <a href="https://www.worldofnumbers.com/threedigits.htm">Squares containing at most three distinct digits, Index entries for related sequences</a>.
%H A053931 Hisanori Mishima, <a href="https://www.asahi-net.or.jp/~KC2H-MSM/mathland/math02/math0210.htm#269">Sporadic tridigital solutions</a>.
%F A053931 a(n) = A053930(n)^2. - _Elmo R. Oliveira_, Jul 17 2025
%Y A053931 Cf. A053930.
%K A053931 nonn,base
%O A053931 1,1
%A A053931 _Patrick De Geest_, Mar 15 2000
%E A053931 More terms from Joe K. Crump (joecr(AT)carolina.rr.com), Sep 07 2000
%E A053931 a(14) onwards added by _Zhao Hui Du_, Mar 01 2024