C

n=sqrt(1+1.3787/(1-0.017842/pow(x,2)))

Python

n=(1+1.3787/(1-0.017842/x**2))**.5

Fortran

n=SQRT(1+1.3787/(1-0.017842/x**2))

MATLAB

n=sqrt(1+1.3787./(1-0.017842./x.^2))

LaTeX

n^2-1=\frac{1.3787λ^2}{λ^2-0.017842}