1.\quad a_n=(n+1)(n-1)! \\
2.\quad a_n=\frac{(-1)^n+2^n}{3n} \\
3.\quad a_n=\frac{8}{3}-\frac{28}{15}\left(-\frac{1}{2}\right)^n+\frac{2^n}{5} \\
6.\quad a_n=(-1)^n m{m\choose n},\quad\sum_{k=0}^m 2^ka_k=(-1)^m m \\
8.\quad 3^{30} \\
9.\quad a_n=\frac{7-3\sqrt{7}}{14}(1-\sqrt{7})^n+\frac{7+3\sqrt{7}}{14}(1+\sqrt{7})^n \\
10.\quad a_n = -\frac{2}{3} (-1)^n+\frac{1}{6} 2^n \\
11.\quad a_n=n^2 \Rightarrow a_{2004}=2004^2 \\
12.\quad\textrm{Rekonstruirati rekurziju preko karakteristi\v{c}ne} \\
\textrm{jednad\v{z}be \v{c}ija su rje\v{s}enja tg15$^\circ$ i
ctg15$^\circ$.} \\
15.\quad\textrm{Proniknuti u kombinatorno zna\v{c}enje pribrojnika u} \\
\textrm{rekurziji.}\ R_n={n\choose 4}+\frac{(n-2)(n-1)}{2} \\
16.\quad a_n=\frac{5-\sqrt{5}}{10}\left(\frac{1-\sqrt{5}}{2}\right)^n+\frac{5+\sqrt{5}}{10}\left(\frac{1+\sqrt{5}}{2}\right)^n