I'm trying to prove a property involving the parity of a binomial coefficient using Lucas' theorem. For this, let $r=\lfloor \log_2(k_s)\rfloor+1$, with $k_s\geq2$. We know that if $0\leq i\leq 2^{r}-1$, then Lucas' theorem implies that $\binom{i+2^r}{k_s}\equiv\binom{i}{k_s}\binom{1}{0}\equiv\binom{i}{k_s}(\text{mod }2)$. The latter relation is clear. What I don't know is how do I prove that,
\begin{equation} \binom{k_s+2^{r-1}}{k_s}\equiv0(\text{mod }2) \end{equation} using Lucas' theorem. I hope anyone can help me. I would appreciate any help that you can give me to clarify this.