a(n+1)-3(n+1)+2=1/3an+2n+5/3-3(n+1)+2
a(n+1)-3(n+1)+2=1/3an-n+2/3
a(n+1)-3(n+1)+2=1/3(an-3n+2)
[a(n+1)-3(n+1)+2]/(an-3n+2)=1/3
所以an-3n+2是等比数列,q=1/3
an-3n+2=(a1-3×1+2)*(1/3)^(n-1)
an=3n-2+(a1-1)*(1/3)^(n-1)
a(n+1)-3(n+1)+2=1/3an+2n+5/3-3(n+1)+2
a(n+1)-3(n+1)+2=1/3an-n+2/3
a(n+1)-3(n+1)+2=1/3(an-3n+2)
[a(n+1)-3(n+1)+2]/(an-3n+2)=1/3
所以an-3n+2是等比数列,q=1/3
an-3n+2=(a1-3×1+2)*(1/3)^(n-1)
an=3n-2+(a1-1)*(1/3)^(n-1)