A192670 Floor-Sqrt transform of central trinomial coefficients (A002426).

1, 1, 1, 2, 4, 7, 11, 19, 33, 56, 94, 160, 271, 461, 785, 1337, 2279, 3890, 6644, 11357, 19426, 33246, 56930, 97535, 167177, 286665, 491745, 843842, 1448530, 2487302, 4272238, 7340067, 12614059, 21682694, 37279415, 64108676, 110268453, 189700207, 326408942, 561733093, 966869803

Offset: 0

Author

Emanuele Munarini, Jul 07 2011

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 0..1000

Programs

Mathematica

FSFromSeries[f_,x_,n_] := Map[Floor[Sqrt[#]]&,CoefficientList[Series[f,{x,0,n}],x]]
FSFromSeries[1/Sqrt[1-2x-3x^2],x,100]

Formula

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