Binomial Theorem

যদি \(\left(1+x+x^2+x^3\right)^5=\sum_\limits{\mathrm{k}=0}^{15} \mathrm{a}_{\mathrm{k}} \mathrm{x}^{\mathrm{k}}\) হয়, তবে \(\sum_\limits{k=0}^7(-1)^k \cdot a_{2 k}\) হবে