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 A053883 #19 Jul 18 2025 11:55:35
%S A053883 1,16,121,2116,261121,2621161,6222212161,6626611216,6661661161,
%T A053883 26166621121,1221126662116,2121112611216,21122122166161,
%U A053883 662612612216121616,16611262122666122666161,12626261111222162126111612161,2221262216626122626662262611111116211216,2662116111222626216162621266666216222222216621166116
%N A053883 Squares composed of digits {1,2,6}.
%H A053883 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 A053883 Hisanori Mishima, <a href="https://www.asahi-net.or.jp/~KC2H-MSM/mathland/math02/math0210.htm#126">Sporadic tridigital solutions</a>.
%F A053883 a(n) = A053882(n)^2. - _Elmo R. Oliveira_, Jul 18 2025
%Y A053883 Cf. A053882.
%K A053883 nonn,base
%O A053883 1,2
%A A053883 _Patrick De Geest_, Mar 15 2000
%E A053883 More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 04 2005
%E A053883 a(18) from _Zhao Hui Du_, Feb 28 2024