C

n=sqrt(1+2.6041/(1-pow(0.1379/x,2))+4.1237/(1-pow(21.371/x,2)))

Python

n=(1+2.6041/(1-(0.1379/x)**2)+4.1237/(1-(21.371/x)**2))**.5

Fortran

n=SQRT(1+2.6041/(1-(0.1379/x)**2)+4.1237/(1-(21.371/x)**2))

MATLAB

n=sqrt(1+2.6041./(1-(0.1379./x).^2)+4.1237./(1-(21.371./x).^2))

LaTeX

n^2-1=\frac{2.6041λ^2}{λ^2-0.1379^2}+\frac{4.1237λ^2}{λ^2-21.371^2}