restart; # Backwards Differentiation Formula sigma0:=w->w^s; s:=6; logseries:=convert(subs(v=1/w-1,series(log(1+v),v,s+1)),polynom); rho0:=-simplify(sigma0(w)*logseries); beta:=1/coeff(rho0,w,s); sigma:=beta*sigma0(w); rho:=beta*rho3; R:=[solve(rho=0)]; seq(abs(evalf(R[i])),i=1..s);