Describe all k-tuples (n1, n2,...,nk) of natural numbers, k = 1, 2,..., such that complete bipartite graph K(n1,n2,...,nk) is a planar graph.

Question

I have tried this question by drawing different graphs and guessing but nothing general in is coming to be true for all complete bipartite graphs.

Question- Describe all k-tuples $(n_1, n_2,...,n_k)$ of natural numbers, $k = 1, 2,...,$ such that complete bipartite graph $K(n_1,n_2,...,n_k)$ is a planar graph.