On the Pentomino Exclusion Problem

In this paper we are interested in the Pentomino Exclusion Problem due to Golomb: Find the minimum number of unit squares to be placed on ak\times nchessboard so as to exclude all pentominoes . Using an appropriate definition of density of a tiling, we obtain the asymptotic value of this number, and we establish this number for the k\times n chessboard when k≤ 4 .