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%I #12 Feb 15 2020 10:52:26
%S 0,64,54000,48387776,43449047520,39017102749504,35037312017058000,
%T 31463467090220398016,28254158407188855215040,
%U 25372202786113074403284544,22784209847768873321556750000
%N Values X satisfying the equation 7(X-Y)^4-8XY=0, where X>=Y.
%C To find Y values: b(n) = c(n)*(-1+d(n)) which gives: 0, 56, 53760, 48380584, 43448832000,...
%H G. C. Greubel, <a href="/A123394/b123394.txt">Table of n, a(n) for n = 0..335</a>
%F a(n) = c(n)*(1+d(n)) with c(0) = 0, c(1) = 4 and c(n) = 30*c(n-1) - c(n-2), d(0) = 1, d(1) = 15 and d(n) = 30*d(n-1) - d(n-2).
%F From _Max Alekseyev_, Nov 13 2009: (Start)
%F a(n) = 2*A123393(n)
%F For n>=4, a(n) = 928*a(n-1) - 26942*a(n-2) + 928*a(n-3) - a(n-4).
%F O.g.f.: 16*x*(4*x^2 -337*x +4)/((x^2 -30*x +1)*(x^2 -898*x +1)). (End)
%t CoefficientList[Series[16*x*(4*x^2 - 337*x + 4)/(x^2 - 30*x + 1)/(x^2 - 898*x + 1), {x, 0, 50}], x] (* _G. C. Greubel_, Oct 13 2017 *)
%o (PARI) x='x+O('x^50); concat([0], Vec(16*x*(4*x^2 -337*x +4)/((x^2 -30*x +1)*(x^2 -898*x +1)))) \\ _G. C. Greubel_, Oct 13 2017
%K nonn
%O 0,2
%A _Mohamed Bouhamida_, Oct 14 2006
%E More terms from _Max Alekseyev_, Nov 13 2009
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