Let $$\{a_n\}_{n=0}^{\infty}$$ be a sequence such that $$a_0 = a_1 = 0$$ and $$a_{n+2} = 2a_{n+1} - a_n + 1$$ for all $$n \geq 0$$. Then, $$\sum_{n=2}^{\infty} \frac{a_n}{7^n}$$ is equal to

A

$$\frac{6}{343}$$

B

$$\frac{7}{216}$$

C

$$\frac{8}{343}$$

D

$$\frac{49}{216}$$