Normal zeta functions of the Heisenberg groups over number rings I - the   unramified case
  Let $K$ be a number field with ring of integers $\mathcal{O}_K$. We compute explicitly the local factors of the normal zeta functions of the Heisenberg groups $H(\mathcal{O}_K)$ that are indexed by rational primes which are unramified in $K$. We show that these local zeta functions satisfy functional equations upon the inversion of the prime. 
Michael M. Schein, Christopher Voll
math.GR math.CO