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 A023112 #21 Feb 12 2021 06:04:32 %S A023112 0,144,207936,299843856,432374632704,623483920515600, %T A023112 899063381008862784,1296448771930859619216,1869478230060918562046976, %U A023112 2695786311299072635612120464,3887321991415032679634115662400 %N A023112 Squares that remain square when the digit 4 is appended. %C A023112 The terms of the sequence are the squares of the y-values in the solution to the Pellian equation x^2-10*y^2=4. - _Colin Barker_, Sep 28 2013 %F A023112 Empirical g.f.: -144*x^2*(x+1) / ((x-1)*(x^2-1442*x+1)). - _Colin Barker_, Jan 31 2013 %F A023112 a(n) = 4*A023111(n). - _Colin Barker_, Sep 28 2013 %K A023112 nonn,base %O A023112 1,2 %A A023112 _David W. Wilson_