Find the sum of $$ 1 + 2\left( \dfrac{1}{3} \right) + 3\left( \dfrac{1}{3} \right)^2 + 4\left( \dfrac{1}{3} \right)^3 + \ldots + n\left( \dfrac{1}{3} \right)^{n - 1} + \dots $$

Find the sum of

$$ 1 + 2\left( \dfrac{1}{3} \right) + 3\left( \dfrac{1}{3} \right)^2 + 4\left( \dfrac{1}{3} \right)^3 + \ldots + n\left( \dfrac{1}{3} \right)^{n - 1} + \dots $$