8.
设集合\(M=\{-1,0,1)\),集合\(A_{n}=\{(x_{1},x_{2},x_{3},…,x_{n})|x_{i}∈M\),\(i=1\),\(2\),\(…\),\(n\}\),集合\(A_{n}\)中满足条件“\(1\leqslant |x_{1}|+|x_{2}|+…+|x_{n}|\leqslant m\)”的元素个数记为\(S_{m}^{n}\).
\((1)\)求\(S_{2}^{2}\)和\(S_{2}^{4}\)的值;
\((2)\)当\(m < n\)时,求证:\(S_{m}^{n} < {{3}^{n+1}}+{{2}^{m+1}}-{{2}^{n+1}}\).