limn→∞[11•4+14•7+17•10+…+1(3n−2)(3n+1)]=______.

limn→∞[11•4+14•7+17•10+…+1(3n−2)(3n+1)]=______.

limn→∞[11•4+14•7+17•10+…+1(3n−2)(3n+1)]=limn→∞13[(1−14)+(14−17)+…+(13n−2−13n+1)=limn→∞13(1−13n+1)=limn→∞13•3n3n+1=13.故答案為13.