Can someone please help me with this problem?

Suppose that the function f satisfies the recurrence relation

2 * f ( sqrt(n) ) + log(n)

whenever n is a perfect square greater than 1 and f(2) = 1

For this problem I am asked to find f(16).

If I pluged in n = 16 into the function above I will get

2 * 4 + log(16) which equals to aprox. 9.204

9.204 is not a perfect square so does that mean when n=16 there is no answer?

I believe that we are supposed to plug the given n into the function and find its value, then if it is a perfect square, we plug that into the function again until that value is not a perfect square. Would this be correct?

Thank you very much for your help!