1.已知数列{An}满足{An/n}是公差为1,的等差数列,且An+1=(n+2/n)·An+1
(1)求数列{An}的通项公式An;(2)设Bn=(-1)^n·An,求数列{Bn}的前n项和Sn
2.在数列{An}中,若A1=1,An-A(n-1)=n-1,则An等于什么?