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Floor-Sqrt transform of central trinomial coefficients (A002426).
1

%I #7 Feb 28 2017 00:32:26

%S 1,1,1,2,4,7,11,19,33,56,94,160,271,461,785,1337,2279,3890,6644,11357,

%T 19426,33246,56930,97535,167177,286665,491745,843842,1448530,2487302,

%U 4272238,7340067,12614059,21682694,37279415,64108676,110268453,189700207,326408942,561733093,966869803

%N Floor-Sqrt transform of central trinomial coefficients (A002426).

%H G. C. Greubel, <a href="/A192670/b192670.txt">Table of n, a(n) for n = 0..1000</a>

%F a(n) = floor(sqrt(trinomial(2*n,n))).

%t FSFromSeries[f_,x_,n_] := Map[Floor[Sqrt[#]]&,CoefficientList[Series[f,{x,0,n}],x]]

%t FSFromSeries[1/Sqrt[1-2x-3x^2],x,100]

%K nonn

%O 0,4

%A _Emanuele Munarini_, Jul 07 2011