%I #22 Feb 12 2021 06:04:54
%S 0,4,16,324,6400,23716,467856,9229444,34199104,674648676,13308852496,
%T 49315084900,972842923584,19191356070436,71112318227344,
%U 1402838821160100,27673922144716864,102543913568745796,2022892607269941264
%N Squares that remain square when the digit 9 is appended.
%C The terms of the sequence are the squares of the y-values in the solution to the Pellian equation x^2-10*y^2=9. - _Colin Barker_, Sep 28 2013
%F Empirical g.f.: -4*x^2*(x+1)*(x^4+2*x^3+75*x^2+2*x+1) / ((x-1)*(x^6-1442*x^3+1)). - _Colin Barker_, Jan 31 2013
%Y Cf. A023111, A023112, A023113.
%K nonn,base
%O 1,2
%A _David W. Wilson_
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