Hi Anila,

Let x and y be the 6th and 5th term of the series respectively.

x^2-y^2=221

(x+y)(x-y)=17*13

x+y=17

x-y=13   solving these two equations we get x=15 ,y=2.

now ,7 th term =17,8 th term=32,9 th term=49,10 th term=81.