Given that the general term formula of the sequence {an} is an = n / N ^ 2 + 156 (n belongs to positive integer), what is the maximum term of the sequence

Given that the general term formula of the sequence {an} is an = n / N ^ 2 + 156 (n belongs to positive integer), what is the maximum term of the sequence

a(n)=n/[n^2 + 156] = 1/[n + 156/n]