A192684 Floor-Sqrt transform of numbers of A004148 (secondary structures).

1, 1, 1, 1, 2, 2, 4, 6, 9, 13, 20, 31, 47, 73, 112, 174, 269, 418, 651, 1015, 1586, 2481, 3886, 6095, 9571, 15048, 23684, 37312, 58837, 92857, 146667, 231831, 366707, 580438, 919314, 1456898, 2310137, 3665024, 5817475, 9238469, 14677875, 23329993, 37097578, 59013025, 93910464, 149498476

Offset: 0

Author

Emanuele Munarini, Jul 07 2011

Keywords

• nonn

Programs

Mathematica

FSFromSeries[f_,x_,n_] := Map[Floor[Sqrt[#]]&,CoefficientList[Series[f,{x,0,n}],x]]
FSFromSeries[(1-x+x^2-Sqrt[1-2x-x^2-2x^3+x^4])/(2x^2),x,100]

Formula

a(n) = floor(sqrt(A004148(n))).