1. A phase change non-volatile memory device comprising: a memory array with a plurality of memory cells including phase change material and arranged in rows and columns; a column decoder and a row decoder configured to select columns, and, respectively, rows of the memory array during operations of programming of corresponding memory cells; and control logic, coupled to the column decoder and the row decoder, and configured to execute a sequential programming command to control the column decoder and row decoder to select one column of the memory array and execute sequential programming operations on a selected block of memory cells belonging to a number of contiguous selected rows of the selected column, wherein the control logic is configured to define the selected block based on a variable block size value corresponding to the number of contiguous selected rows.