EN
Let K be an algebraic number field with non-trivial class group G and $𝓞_K$ be its ring of integers. For k ∈ ℕ and some real x ≥ 1, let $F_k(x)$ denote the number of non-zero principal ideals $a𝓞_K$ with norm bounded by x such that a has at most k distinct factorizations into irreducible elements. It is well known that $F_k(x)$ behaves for x → ∞ asymptotically like $x(log x)^{1-1/|G|} (log log x)^{𝖭_k (G)}$. We prove, among other results, that $𝖭₁(C_{n₁} ⊕ C_{n₂}) = n₁ + n₂$ for all integers n₁,n₂ with 1 < n₁|n₂.