A123395 - OEIS

%I #12 Feb 15 2020 10:52:26

%S 0,27,6144,1549125,393289536,99891091323,25371897661440,

%T 6444361377895077,1636842406341623424,415751526662194438875,

%U 105599250926807591663616,26821793983834918021139973

%N Values X satisfying the equation 7(X-Y)^4-16XY=0, where X>=Y.

%C To find Y values: b(n) = c(n)*(-1+d(n)) which gives: 0, 21, 6048, 1547595, 393265152, 99890702709, ...

%H G. C. Greubel, <a href="/A123395/b123395.txt">Table of n, a(n) for n = 0..395</a>

%F a(n) = c(n)*(1+d(n)) with c(0) = 0, c(1) = 3 and c(n) = 16*c(n-1) - c(n-2), d(0) = 1, d(1) = 8 and d(n) = 16*d(n-1) - d(n-2).

%F From _Max Alekseyev_, Nov 13 2009: (Start)

%F For n>=4, a(n) = 270*a(n-1) - 4066*a(n-2) + 270*a(n-3) - a(n-4).

%F O.g.f.: 3*x*(9*x^2 -382*x +9)/((x^2 -16*x +1)*(x^2 -254*x +1)). (End)

%o (PARI) x='x+O('x^50); concat([0], Vec(3*x*(9*x^2 -382*x +9)/((x^2 -16*x +1)*(x^2 -254*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