6.
已知\(\{ \)
\(a_{n}\)\(\}\)是公差为\(3\)的等差数列,数列\(\{ \)
\(b_{n}\)\(\}\)满足
\(b\)\({\,\!}_{1}=1\),
\(b\)\({\,\!}_{2}= \dfrac{1}{3}\),
\(a_{n}b_{n}\)\({\,\!}_{+1}+\)
\(b_{n}\)\({\,\!}_{+1}=\)
\(nb_{n}\).
\((1)\)求\(\{\)\(a_{n}\)\(\}\)的通项公式;
\((2)\)求\(\{\)\(b_{n}\)\(\}\)的前\(n\)项和.