Can you please help me with this question.

a) Consider the random walk on Z with transition probabilities $\displaystyle p_{i,i+1}$ = $\displaystyle p_{i,i-1}$ = 1/2 for

all i.

i) Find an expression for $\displaystyle p_{00}^{t}$ for all t.

ii) Use your answer to part i) to calculate $\displaystyle f_{00}^{t}$ for $\displaystyle t<=6$

Thanks