The ratpolytocoeff(f, x, n) command computes the expression for the nth coefficient of the Taylor expansion about the origin of f as a function of x.

$\mathrm{with}\left(\mathrm{gfun}\right)\:$

$\mathrm{ratpolytocoeff}\left(\frac{1}{1-x-x^2}\,x\,n\right)$

$\sum _{\mathrm{\_\α}=\mathrm{RootOf}\left({\mathrm{\_Z}}^2+\mathrm{\_Z}-1\right)}\left(-\frac{\left(-\frac{2\mathrm{\_\α}}{5}-\frac{1}{5}\right){\mathrm{\_\α}}^{-n}}{\mathrm{\_\α}}\right)$