一道完形填空.Our school is a key middle school in this city.There

一道完形填空.Our school is a key middle school in this city.There are many trees and f____in it.The r___in our school is wide and c___.The classroon building is very big.There are 50 classrooms in the teaching building.The teachers work in the big office buildingAnd we students have classes in the teaching building.There is a playground to play basketball or fottball.
There are about 2000 students in 50 c___in our school.Allthe students in our school work hard.The teachers in this school are very good.They like to h___the students and students love them.
第一步；取一个自然数n1=8，计算n1的平方+1得a1；第二步；算出a1的各位数字之和得n2,计算n2的平方+1得a2·第三步；算出a2的各位数字之和得n3，再计算n3的平方+1得a3·····以此类推，则a2008=?