Let \(a_1, a_2, a_3, \dots\)be sequence of real numbers satisfying \(a_n = a_{n - 1} a_{n + 1}\)for all n>=2. If\( a_1 = 1 + \sqrt{7}\), and \( a_{1776} = 13 + \sqrt{7},\) then determine\(a_{2009}.\)
a_{2009} is equal to 3 - 2*sqrt(7).
I get the following:
Edit: Item number 3 in the list above should be a2/a1 not a2/a3 !
+101 
