Create a formula for a function f(k)\displaystyle {f{{\left({k}\right)}}} that has f(2)=8\displaystyle {f{{\left({2}\right)}}}={8}. Do not give a simple constant function (like f(k)=8\displaystyle {f{{\left({k}\right)}}}={8}) as your answer.

f(k)=\displaystyle {f{{\left({k}\right)}}}=