Question

define a function
\[f \left( n \right)=\frac{ 1 }{\sqrt[3]{n^2+2n+1}+\sqrt[3]{n^2-1}+\sqrt[3]{n^2-2n+1} }\]
for all natural number. find the value of
\[f(1)+f(3)+f(5)+....+f(999999)\]