解
当n=1时,a1=s1=2-3=-1
当n≥2时
an=sn-s(n-1)
=2n²-3n-2(n-1)²+3(n-1)
=2n²-3n-2n²+4n-2+3n-3
=4n-5
当n=1时,a1=4×1-5=-1
∴an=4n-5