I presume you meant [tex]A_2= 1.107(2396.8)- 260= 2393.3.

A closed form for the above

An=2400 (1.107) -260 (1.107^n-1) (n=0,1,2,....)[/quote]

[tex]a_2= 1.107(1.107(2400)- 260)= 2400(1.107^2)- 260(1.07)- 260

It looks to me like is 2400(1.107)^n[tex] minus 260 times the sum of a geometric series. Do you know the formula for that?

[tex]= 2400(1.107)^3

Population predicted 2020 =2290