This paper proposes a variation of the K-Means clustering algorithm, named Population-Based K-Means (PBK-MEANS), which founds its behaviour on careful seeding. The new K-Means algorithm rests on a greedy version of the K-Means++ seeding procedure (g_kmeans++), which proves effective in the search for an accurate clustering solution. PB-K-MEANS first builds a population of candidate solutions by independent runs of K-Means with g_kmeans++. Then the reservoir is used for recombining the stored solutions by Repeated K-Means toward the attainment of a final solution which minimizes the distortion index. PB-KMEANS is currently implemented in Java through parallel streams and lambda expressions. The paper first recalls basic concepts of clustering and of K-Means together with the role of the seeding procedure, then it goes on by describing basic design and implementation issues of PB-K-MEANS. After that, simulation experiments carried out both on synthetic and real-world datasets are reported, confirming good execution performance and careful clustering.