第6题
egin{align}
& {{ ext{a}}_{1}}=1,{{a}_{n}}={{a}_{n-1}}+{{a}_{n-2}}+ldots ldots +{{a}_{1}}(nge 2) \
& {{a}_{n}}={{S}_{n-1}}={{S}_{n}}-{{S}_{n-1}} \
& Rightarrow {{S}_{n}}=2{{S}_{n-1}} \
& ecause {{a}_{1}}={{S}_{1}}=1 \
& herefore {{S}_{n}}={{2}^{n-1}} \
& herefore {{S}_{10}}={{2}^{9}}=512 \
end{align}