C

n=sqrt(2.6399644-0.011645718*pow(x,2)+0.023061733*pow(x,-2)+0.0017348219*pow(x,-4)-0.00013986059*pow(x,-6)+1.391667e-05*pow(x,-8))

Python

n=(2.6399644-0.011645718*x**2+0.023061733*x**-2+0.0017348219*x**-4-0.00013986059*x**-6+1.391667e-05*x**-8)**.5

Fortran

n=SQRT(2.6399644-0.011645718*x**2+0.023061733*x**-2+0.0017348219*x**-4-0.00013986059*x**-6+1.391667e-05*x**-8)

MATLAB

n=sqrt(2.6399644-0.011645718.*x.^2+0.023061733.*x.^-2+0.0017348219.*x.^-4-0.00013986059.*x.^-6+1.391667e-05.*x.^-8)

LaTeX

n^2=2.6399644-0.011645718λ^{2}+0.023061733λ^{-2}+0.0017348219λ^{-4}-0.00013986059λ^{-6}+1.391667\text{×}10^{-05}λ^{-8}